Amanda Platell: Note to the new leader: watch your back

The phones will be running hot all weekend in the Duncan Smith and Clarke camps as they make the final appointments to their prospective Shadow Cabinets. The most fought-over – if arguably the least desirable – job in British politics must be surely be that of the new leader of the Conservative Party.

The result on Wednesday will end a bloody contest. As each man contemplates what could be his last week of freedom there will be moments when he asks himself: "What have I let myself in for? Is leading the Conservative Party back to power an impossible mission? Can this party even be led any more?"

But one can never underestimate a politician's capacity for self-delusion. At least three-quarters of the Shadow Cabinet and half the parliamentary party believe they are the next leader in waiting. I keep hearing talk of ambitious souls who conspire behind closed doors – still. They should realise that if they do not keep their ambitions to themselves and stop squabbling, there will not be a party left to lead.

It used to be said that loyalty was the Conservative Party's secret weapon. These days that weapon is about as deadly as the Bouncing Bomb on a dry lake. My years at William Hague's side taught me that loyalty is at an all-time low in the Conservative Party and that without it, they will never return to power. The backbiting must stop. The other lesson I learnt was that mistakes made early are almost indelible, and the first steps of a party leader are crucial. Here's some free advice to the new leader from a former spin-doctor.

If it's Clarke, change nothing. If it's Duncan Smith (who has my vote), do nothing. The failure of the Conservative Party to return to power has not been due to a failure of spin, but a lack of substance in and connection with the areas that really matter to people and their families.

Clarke should dust down his Hush Puppies, draw deep on that cigar, lift the ban on smoking in Central Office and get on with the business of policy development and knocking hell out of the Government. The foot and mouth fiasco, an escalating asylum crisis, New Labour's hatred of the motorist and the slowing economy should give the new leader enough to be going on with.

Duncan Smith should stick to his navy suit and white shirt, resist all temptation to pull that double-breasted chalk stripe from the back of his wardrobe (he promised me it had gone to Oxfam – has it Iain?), avoid hats of any description, make sure umbrellas are over his head and not in his drinks and never journey within 20 miles of a theme park, unless it's to drop his kids off.

One of the great vulnerabilities of this Government is its dependence on spin. No one believes anything they say any more. The new leader's standard should be all substance and no spin. He will have to hit the ground running, announcing immediately his Shadow Cabinet and a commitment to building on, not destroying, the unity William Hague created on Europe. It would be an act of great folly to ditch the one and only Tory policy that 75 per cent of the electorate agrees with.

The next priority must be a complete review of all policy on the public services. There must be no intellectual or historical no-go areas in the debate on health and education. The Conservative Party has a problem being heard when it talks about failing schools or our third world health service. A conspiracy first of silence, then of cowardice took over and the party was rightly punished for it. Unless we are credible on these issues and stop being seen as the nasty party – or worse still, the irrelevant party – we will remain in Opposition.

There are few that now doubt that the shattering of the party in the 1997 election was underestimated. The uniting and healing process was started by William Hague around core Tory policies on Europe, tax, crime, law and order. That work was just the beginning.

And so to the Shadow Cabinet. Perhaps if William had stayed for a second term, it would have worked out differently. At the time there was a compelling logic to try to break with the past. In the end the New Faces initiative, designed to chuck out the old lags, failed. The new Tory leader would be well advised to look to the balance in his team not simply in terms of mods and rockers, men and women, anti- and pro-Europeans, but also of old and new faces.

The advantages of having a face not associated with the Tory past counts for nothing if the modest abilities and limited experience of those politicians mean they are incapable of laying a glove on the Government. It's time to bring back the big hitters – John Redwood, Michael Howard and Ann Widdecombe. Yes, I know they get a big boo in parts of the left press, but they get big cheers elsewhere. Behind every successful Tory leader there should be some good Tory women, and Eleanor Laing, Julie Kirkbride and Cheryl Gillan all spring to mind. The new leader should also ensure that there are high-profile roles for the undeniable talents of Andrew Lansley, Liam Fox and Tim Collins.

And at a time of acute talent shortage, can we seriously allow men such as Archie Norman to wallow on the backbenches? Forget the think tank, Archie – the thinking should be going on inside the leadership. I don't envy the task, but someone will have to convince David Davis that his country needs him – inside the Shadow Cabinet or in a senior party job, not dabbling on the edges with Public Accounts Committees.

You may be thinking there's one person missing from this list. It will be difficult to lure William Hague back to a frontline job in the immediate future. But the Conservative Party cannot afford to waste his talents. I predict William will be an important independent figure in the coming years. A smart leader would move heaven and earth to get him into one of the top jobs.

There's no time to waste on celebrations. By the end of this week the new leader should be working on the second or third draft of his conference speech. Perhaps even more importantly he should be making sure that reports of Lady Thatcher's decision to stay away are accurate. The leader needs a chance to begin his tenure with a conference which is not overshadowed by the greatness and guilt associated with its most famous prime minister.

The message must be: the Lady's not for returning. If, as I predict, the new leader is Iain Duncan Smith, I'm sure she will oblige. If it's Ken, I suspect nothing will keep her away.