"I can make Tony Blair, Michael Howard, Charles Kennedy or anyone else look bumbling, irrelevant, tetchy... or rather brilliant," reads the somewhat grand Marr quote.
The real Andrew Marr shifts uneasily when the contents of the T-shirt are put to him, but acknowledges the accuracy of the comment. Appearances on T-shirts, he accepts, are part of the price of giving up the relative anonymity of newspapers to stand in front of the television cameras and have "a level of trivial celebrity" thrust upon you.
"The first thing that happens is you get the sense that the world has stolen your face, that it doesn't belong to you any more. It's public property," says one of the most memorable faces on BBC television.
It is, he acknowledges, both flattering and difficult at the same time, that strangers who think they know you assume they have the right to sit down and engage you in instant conversation. Marr enjoys telling how a man once told him he looked a bit like Andrew Marr - before adding "poor bugger".
But there is a serious side to this fame business that can lead to non-trivial delusions. "I think the biggest problem is trying to retain a sense of perspective, of realising it's not because you've changed and suddenly have become brilliant and interesting in a way you weren't before," says Marr. "It's only because television is a vast multiplication device that is ratcheting up ludicrous numbers of Andrew Marrs splattered all over the place."
Clearly the self-confessed political junkie is prepared to accept the sacrifice, the almost Faustian deal, and appear for ever longer periods, and even more prominently, on the vast multiplication device.
If he was having his own personal T-shirt designed, it would probably highlight, not one of his own felicitous utterances, but a favourite saying of his grandfather's. "There is a cure for everything except a swelled heed," the old man used to say. Marr, the grandson, accepts the warning and understands it is always something you have to watch for - especially when doing interviews about a raft of new Andrew Marr television programmes.
Marr is going in for an ambitious degree of brand extension, not just filling Sir David Frost's empty seat, but also planning to pick up where Simon Schama left off in his A History of Britain. Marr will soon be at work on five one-hour documentaries, a big television history of post-war Britain, an authored series with a very clear perspective.
One of the themes will be of a Britain Lost and Found. "I do think that after a period of enormous soul-searching and unhappiness we may be settling down into a new sense of ourselves although there will always be so many 'ifs' and 'buts' and 'nevertheless' and 'on the other hand' to any of these grand statements." There will also be a documentary on The Enlightenment plus other assorted, as yet unspecified, BBC things under a specially tailored BBC staff contract.
For now, the concentration is totally on this Sunday when Marr's new "Frost" programme, rather neutrally called Sunday AM, goes on air for the first time. Marr's producer, Barney Jones, who also produced Breakfast With Frost for all 11 years of its run, says the aim is to produce something new. He does not want the new programme to be seen as Breakfast With Frost Mark II. That show was put to bed at Easter with appropriate rituals.
"We have a different set, different titles, we have different music. I am hoping that the thing will feel pacier and that we will draw in a younger audience. It will have a greater degree of vibrancy and that will shine through in the whole way we do it," Jones explains.
Will the questions be -how can it be put? - perhaps more pointed, more challenging? "I cannot usefully talk about that," says Jones, traversing with skill the land mines between the old world and the new.
The ghost of Sir David still lingers and there is a determination to show the grand old master of the art of the more gentle style of interviewing continuing respect - even though the reality is that he was bundled out the door, politely bundled, but bundled all the same.
As Sir David, aged 66, who will conduct half a dozen big interviews a year for the BBC, put it at the time of departure: "We had a discussion about it and I was persuaded that this was the way to go. I couldn't really tell you who came up with the idea first, but I was persuaded in the course of the conversation. I was persuaded in the sense that I decided. I decided more than I was persuaded. I think there was a bit of both."
Barney Jones is the first to accept that things will not be the same - not the same at all. In the old days, when he called a very senior press officer at the White House seeking an interview with the president of the United States, and said it was a call from Sir David Frost's office, there was a certain resonance, a certain impact. For all his merits, the name of Andrew Marr doesn't quite ring the same bells - at least for now. The same lack of recognition will almost certainly apply to the likes of President Putin, even though the Queen has noted that Marr looks a lot like the former KGB officer.
The new Sunday interviewer is not despondent, although he acknowledges that he is no Frost. For a start Marr, 46, can do shorthand and has had the useful journalistic life experience of grinding out mundane stories against the clock - something that has never troubled Sir David.
"I'm not going to concede yet that I won't [land the big interviews] but it will obviously be harder. Frost is a broadcasting legend. He has been around forever and started so young. He has a big heft in the States in particular," says the young pretender.
In turn, Marr, who is interested in all the arts but not sport, will give what he has to offer - an intricate knowledge of the UK political system and more film, music and book people. There will be some change to the personnel on the show, reflecting the fact that Marr was three years old when Frost was beginning his journey to television immortality, and his musical icons will clearly be different. Another big change will involve a lot more mingling.
Frost's political, cultural and rock music guests tended to mingle over breakfast after the programme was over, when Sir David enjoyed his first big, fat cigar of the day. "I'd like them to mingle a little bit more in front of the cameras," says Marr.
Marr has already got his bids in for guests and you can be sure Sunday AM will launch with a senior cabinet minister. Which one will, to some extent, depend on how events unfold over the next few days. It will not be the Prime Minister. Marr wants Tony Blair to come on the programme during the Labour Party conference.
As Marr comes in out of the rain and moves into the studio, he knows his working life is going to change dramatically and take on a different pace yet again.
After years of editing and writing columns and expressing opinions, he had been desperate to get back to reporting as BBC political editor.
"I was bored witless with my own views and I needed, almost physically, to get back to the coalface of facts, following stories in detail, in close-up, day after day after day. And I am a political junkie and it was a wonderful thing to do," he says.
The disadvantage is that on big story days he sometimes started at 7am on the Today programme and ended up on the Ten O'Clock News, with as many as 15 different broadcasts in between. There was precious little time for reflection and it was also very tiring. "I am pretty workaholic but even for me it was stupid," Marr accepts.
Unlike journalistic colleagues in Westminster such as Adam Boulton of Sky, Trevor Kavanagh of The Sun or Chris Moncrieff of the Press Association, who seem to follow the political circus forever, Marr says he feels the need to do something new every five years or so.
The Glasgow-born journalist, who is married to the political commentator Jackie Ashley and has three children, says he also wants to understand how the whole process fits together, historically as well as politically. It will also be nice in future to be able to ask Tony Blair more than a few snatched questions.
"I am going to carry on lunching and watching and talking. I am not going to disconnect from Westminster and the political world. I know these guys and I've known them in some cases for more than 25 years. It's not like I am suddenly going to cut off from them - I won't," says Marr.
He believes he is leaving BBC political reporting in good hands, following the appointment of ITV News's combative Nick Robinson as his successor. The appointment, he believes, sends an important post-Hutton message."If the BBC was in a rather twitchy, rather craven mood about politics, I don't think they would have wanted Nick Robinson as my successor," he says.
In fact, he is convinced that the BBC has not lost its political nerve in the wake of the "Shakespearian tragedy" of the Gilligan affair, and can cite three of his own exclusive stories to support his case.
There were protests from Downing Street when Marr reported, long before the formal admission, that the Government had accepted there were no weapons of mass destruction in Iraq. It wasn't terribly pleased either when Marr reported that there had been a deal done between Blair and Brown effectively giving up on the euro.
The third was a little less weighty but just as much fun. Marr predicted accurately that Alastair Campbell was leaving Downing Street and got the timing right, to the day, despite the issuing of classic non-denial denials from Number 10.
"I only use them as examples of stories that, if the BBC had been neutered, I think I would have found difficulty getting on air. Far from it," says Marr with relish.
He does believe that there is something wrong in the relationship between journalists and politicians, and tells the story of his father planting a rose and surrounding it with stakes for support. The rose bush died but one of the stakes grew. He does not, however, go along with the thesis put forward by journalist John Lloyd that journalism is undermining democracy by trying to supplant the role of politicians.
Marr who describes himself as "a sort of Cromwellian Parliamentarian" believes that a lot of what went wrong in recent years was the fault of politics and the spin-doctoring culture. The Major government was mocked to death when both anti-and pro-Conservative newspapers combined to attack it, and New Labour successfully created "a narrative of sleaze" which finally saw it off.
Labour's great mistake, Marr believes, was to believe that journalists would then move on and treat the new government with attention and respect.
"John [Lloyd] cuts out the political reasons behind his political narrative and therefore throws far too much blame onto editors and reporters for what happened," says Marr, who was editor of The Independent for two years from 1996.
In his book My Trade, Marr admits that he did not see himself as a grade-A editor. He concedes wistfully that he rather hoped that people all over London would contradict him and insist that he had been a wonderful editor after all. But there was silence.
He recalls advice on the subject from Sir Simon Jenkins, who told him there were people who liked to achieve things through others, through management, and there were the egotists who like hopping around at the front of the stage.
"He told me I was one of the latter and he was absolutely right about it," says Marr, who is nonetheless proud of his difficult days editing The Independent when ownership was split between David Montgomery's Mirror Group and Sir Anthony O'Reilly's Independent News and Media group. Marr's demise came after he opposed a Montgomery plan to get rid of most of the paper's sub-editors to cut costs.
"If I had agreed the package of cuts, I think The Independent would not have survived as a proper newspaper. I had to fight. I had to be fired," says Marr, who believes there was a good outcome. The row provoked, he believes, a crisis within Mirror Group, which allowed Sir Anthony to take over.
The front-of-stage egotist side of his character can get him into even worse jams than editing. The most colourful example was his public pronouncements at the Hay-on-Wye literary festival that newsreaders were overpaid for what they do.
He had been asked whether people in the media were overpaid. Self-deprecatingly he agreed that he probably wasn't worth what he received, but then he went that step further by saying that he had never quite understood "why reading an autocue, however adeptly, earns you quite as much money" and he was greeted with laughter and applause.
"I have a natural tendency to burble on at length. I am a show-off. Everybody in television is a show-off and I like people to respond to pirouetting sentences. It was a stupid thing to say," says Marr, who had to quickly fire off contrite e-mails to the autocue readers.
He stands by more recent controversial statements criticising many MPs for their inability to speak "crisply, clearly, vividly". They should learn to speak "fluent human", Marr advised.
As he moves towards his new life, where the phones are a little less likely to ring 24 hours a day, Marr's new work schedule is unlikely to leave him time to get bored.
Friday through to Sunday will be largely devoted to Sunday AM and then it is straight into Start The Week on Radio 4 on Monday mornings. Start The Week requires a lot of research. Marr takes the view that if someone has written a book and comes onto the programme, he ought to have read it rather than rely on briefing notes.
Then the middle of the week will be devoted to making television documentaries. "I am going to have to be pretty disciplined," says Marr, an obsessive runner who pounds out up to 25 miles a week and has successfully completed the Amsterdam marathon.
But will his new change of life be a middle-distance challenge or more like a Frost marathon?
"If it suits, I can see myself doing this for a long time. If it suits the BBC, that is. If it suits both of us," says Marr with a diplomatic smile.