Sir Keir Starmer will hand the vote to millions of EU citizens if Labour wins the next general election, the Telegraph can reveal.

Under manifesto plans for the biggest expansion of the franchise in almost a century, Sir Keir will launch a “package of proposals” including votes for settled migrants and 16 and 17-year-olds.

The move could force the Conservatives out of London altogether and unseat Boris Johnson if he stands again for Parliament in 2029.

However, the Labour leader faces accusations of trying to “rig the outcome” of a future election and “laying the groundwork for a referendum to rejoin the EU”.

Under the proposals, migrants who live permanently in the UK and pay tax will be able to vote in general elections for the first time.

It is expected to affect around 3.4 million EU nationals in Britain, who have already fulfilled those requirements to achieve “settled status”. A further 2.6 million have already been granted “pre-settled” status and could be given voting rights in the future.

Labour would also expand the franchise to include 1.4 million 16 and 17-year-olds, increasing the size of the electorate by more than eight per cent in total.