Britain will face “dire consequences” if it does not secure a clean departure from the European Union, Theresa May warned as she packed her manifesto for next month's general election.

The Prime Minister said that if the Tories win the general election her Government would “not seek to fudge this issue - to be half-in and half-out of the EU”.

She committed the Tories to taking Britain completely out of both the single market and the customs’ union, and cutting net immigration into the UK to fewer than 100,000 a year, something she failed to do in her six years as home secretary.

The strength of the commitment in the manifesto will make it very hard for the House of Lords, where the Tories do not have a majority, to frustrate her Brexit plans when they are voted on by peers.

Mrs May said that securing the best deal for Britain outside the EU was the single most important challenge facing her Government over the next five years.

Brexit is listed as one of five "giant challenges" in the Conservative manifesto, alongside the economy, social divisions, an ageing society and technology.