After almost four years in which Brexit has dominated British politics, the word itself will be largely banned within government from next month, an official said on Tuesday.

Parliament is expected to ratify Prime Minister Boris Johnson's plan to leave the European Union in the next two weeks, paving the way for Britain's departure from the bloc on January 31.

London must still thrash out the terms of its future trading relationship with Brussels but Johnson and his team are determined to move on to other things.

One official, speaking on condition of anonymity, said the word “Brexit” would be used as sparingly as possible.

"You won't hear the word cross my lips after January 31," the official said.

After a victorious election campaign in which he spoke of little else, Johnson avoided the word in his Christmas message, although it appeared in his New Year's statement.

The Sunday Times reported at the weekend that the taskforce negotiating Britain's future ties with the EU would also avoid the word, and would be known simply as "Taskforce Europe".

"Brexit" was named word of the year by dictionary publisher Collins in 2016, as usage surged by more than 3,400 per cent before, during and after the referendum on EU membership.

Collins described it as "arguably politics' most important contribution to the English language [...] since the Watergate scandal gave commentators and comedians the suffix '-gate'."