A short gas-lit street of 13 terraced houses, it is the most sought-after address for politicians and aspiring power-brokers - after Downing Street. It was once plain North Street, but in 1937 was given the prefix "Lord" because there were too many North Streets. This action, perhaps a little joke on the part of Westminster's councillors, thus gave it the name of Britain's worst ever Prime Minister.
Built in 1722, its Georgian houses are small - three or four bedrooms - with no gardens and little space for car parking. Such is the demand, however, that these days they change hands for about pounds 750,000.
Always in demand by would-be prime ministers, it was Harold Wilson who put the street on the map, when he moved there soon after losing the 1970 general election. Wilson was pleased with his new abode. In his authorised biography, Philip Ziegler wrote: "Except for the first-floor drawing room, the rooms were small and the house was on five storeys, but it was unequivocally grand. Since the lease was for 20 years the price was only pounds 20,000, but the upkeep, and the expenses of Mrs Pollard, the housekeeper who lived in the basement, took up a great part of Wilson's available income."
In 1974, when Harold Wilson was unexpectedly re-elected Prime Minister, Mary Wilson decided she did not want to move back to Downing Street and so No 10's business effectively moved to No 5.
Today, the nearest Labour grandee is Roy Hattersley in parallel Gayfere Street. Otherwise, Lord North Street and its surrounding web of streets is almost solid Tory.
If during his presumably short tenure at No 11, Mr Portillo runs out of sugar, he can ask his near neighbour Jonathan Aitken at No 8. Once the home of Brendan Bracken, Churchill's information supremo and Financial Times chairman, Mr Aitken's house has seen more than its fair share of intrigue. Alternatively, Mr Portillo could cross the road and knock on Teresa Gorman's door or a few houses away, Alastair Goodlad's.
Mr Goodlad's house was once owned by Lady Sybil Colefax, famous for a prank in which she invited George Bernard Shaw and HG Wells, who loathed each other, to the same party, having sent each writer a postcard informing them that the other had expressed a burning desire to meet them.
On 27 September 1939, three weeks after the beginning of the Second World War, Lady Colefax held a discreet lunch at No19 for the Duke and Duchess of Windsor.
Nearer still to Mr Portillo are the Bottomleys. Recent arrivals to this political equivalent of Brookside Close, Peter and Virginia live in Smith Square, their kitchen wall backing on to No 11 Lord North.
Mr Portillo will not be short of advice on dealing with the press - he is positively surrounded by media big-wigs. Henry Keswick, a former Spectator proprietor, lives next door, Lord Rees-Mogg, a former Times editor, is just across the way.
At the other end of the road, in Cowley Street, are Sir David English, the Associated Newspapers chief, and Lord Hartwell, who used to own the Daily Telegraph. Despite its proximity, Cowley Street may not be visited by Mr Portillo: No 13 is the Major campaign HQ.