Beating all the odds, Harry becomes Prime Minister following a landslide victory in the 1989 general election, and sets out to dismantle media monopolies, establish Britain as a neutral country through withdrawal from NATO, the removal of American military bases from British soil and unilateral nuclear disarmament, achieve public control of finances, revive manufacturing by withdrawing from the Common Market and imposing import controls, and create an open government.

After Perkins undiplomatically rejects the pleas of the US Secretary of State to reconsider his defence policies, a run on pound sterling and a resultant balance of payments crisis are engineered to discredit him, with the US and other NATO members refusing to offer standby credit.

Foreign Secretary Tom Newsome, feigning illness, embarks on a secret tour of Algeria, Libya and Iraq, securing £10,000,000,000 in standby credit in support of Labour's policies of the removal of American military bases and the creation of a Palestinian homeland.

Although Perkins is reluctant to accept Newsome's resignation, he is left with no choice after the story is reported in the newspapers, implying a security threat due to Maureen's flatmate being a member of the Workers' Revolutionary Party.

Smith is an asset of American intelligence, having secured his loyalty through paid lecture tours, and is opposed to Perkins' policies of abolishing the House of Lords and the honours system due to his personal desire for a peerage.

With newspaper magnate Sir George Fison and BBC editor Jonathan Alford, amongst others, ensuring media support for Smith's case (which they depict as comparable to Lech Wałęsa's and Solidarity's), the resultant blackouts and Perkins' refusal to deploy soldiers as strike-breakers seriously damages the government's approval rating.

Perkins' premiership is brought to an end by an accident at the experimental Windermere nuclear power station, which threatened to contaminate an area including Blackpool and Liverpool with radiation.

With the King appointing the former as Prime Minister on the advice of DI5, Wainwright replaces the entire Cabinet and abandons most of Perkins' policies, much to the jubilation of the conspirators who cheer their achievement of 'a very British coup'.