The short answer is: With great difficulty. As prime minister, Nigel Farage would have unique demands on his time from the media, interest groups and foreign governments, plus exhorting businesses to do their bit to make the economy grow. This leaves little time for scrutinizing draft legislation line by line or dealing with the complexities of public finance. Farage would need about one hundred ministers to deliver the promises he has talked about. For example, the Department for Business and Trade has a total of seven ministers to deal with its work and the 19 agencies and public bodies for which it is responsible.
To succeed ministers need to defend their actions against questioning in the Commons by hundreds of experienced MPs representing six opposition parties. Whatever the size of Reform's majority, one thing is certain: 98 percent of its MPs would be new to the House of Commons and virtually 100 percent will be new to Whitehall departments. While the great majority of Keir Starmer's Cabinet had never been even a junior minister, nearly all were experienced in the rough and tumble of debate in Parliament and in print, broadcast and social media.
At present Reform has only five MPs, three with experience in financial affairs and two in local government. Like any parliamentary party, they differ in the promise they show for rapidly taking charge of a Whitehall department such as the Treasury, the Foreign Office or the Home Office.
Up to a point the prime minister can turn to the House of Lords for help. Some ministerial posts could be filled with peers who have previously been in government. He could also give peerages to qualify wealthy business supporters as ministers. However, the record of businessmen-turned-politicians shows that many fail to adapt to a change in roles. In any event, a peer in charge of a Whitehall department would need a deputy minister to answer questions on their behalf in the House of Commons.
Nigel Farage has four years to recruit two dozen more or less competent Cabinet ministers, since Keir Starmer will not want to call a general election until 2029, as long as Electoral Calculus predicts that if a general election were held tomorrow a majority of Labour MPs would lose their seats.
Plans have been announced for Reform to set up a think tank to prepare policies that a Reform government can introduce. However, the Starmer government has shown that such support need not enable a new government to hit the ground running, and Liz Truss's reliance on think-tank ideas hit the skids with extraordinary speed.
The civil service, the core of the so-called deep state, prepares draft policies to implement the promises of a newly elected government. However, many experts question whether Farage's generous proposals to cut taxes and increase spending are possible. In that case, Nigel Farage's populist bonhomie will run hard up against advice coached in Yes, Minister language.
Four years allows ample time for Conservative politicians to decide whether they want to return to government as Reform ministers or face another five years in Opposition. Those ambitious to become ministers will need to switch their allegiance to Reform before too long in order to be re-elected as a Reform rather than a Conservative MP. If they wait until after the next election to switch parties, they are likely to become ex-MPs, as a Reform victory would reduce the Tory party to the fifth-largest party in Parliament with about two dozen MPs.
Prof Richard Rose, University of Strathclyde is Britain's senior election expert. He is writing a book on the disruption of the British party system.