THERESA May has reaffirmed her commitment to cutting annual net migration to a "sustainable" level in the tens of thousands as she again emphasised how the General Election was about securing strong and stable leadership.

Questions have been raised about whether or not the Conservative Government’s controversial commitment on immigration would feature in the party’s manifesto after the Prime Minister’s Cabinet colleague Karen Bradley suggested the issue was "not about numbers" but about ensuring Britain had the skilled workers it needed.

However, speaking during an election visit to a radar manufacturer in Enfield, in north London, Mrs May insisted: "We want to see sustainable net migration in this country; that sustainable net migration is in the tens of thousands.

Loading article content

"Leaving the European Union enables us to control our borders in relation to people coming from the EU, as well as those who are coming from outside."

The PM – buoyed by the latest poll, which has given the Tories a 24-point lead over Labour - has been coming under pressure to confirm that David Cameron's controversial pledge would feature in the forthcoming Tory manifesto.

She has always maintained her support for the target of reducing net migration - the total amount of incomers to the UK each year minus the number leaving the country - below 100,000, despite failing to hit it during her six years as Home Secretary.

Earlier, Ms Bradley told Sky News: "What we need is to have the right people, to attract the brightest and best. It's not about putting numbers on it, it's about making sure we can deliver where industries need skills, where the brightest and best want to come to Britain."

Later, a spokesman for the Secretary of State made clear she was not speculating about what might be in the Conservative manifesto and that the Government commitment had not changed.

Some Tory colleagues have been pressing Mrs May to exclude international students from the migration figures as this would involve a significant fall.

There have also been suggestions that the PM would offer a concession over including students in the immigration target as part of efforts to get remaining legislation, the Higher Education and Research Bill, through Parliament before it finished ahead of the election.

But a Whitehall source stressed: "Any suggestion we are going to change our approach to the inclusion of overseas students in the migration statistics is plain wrong."

On the stump, Mrs May again put the issue of leadership at the heart of her campaign, declaring: "This election is about ensuring that we have strong and stable leadership in this country in the national interest. It's about strengthening our negotiating power for Brexit and it's about sticking to our plan for a stronger Britain, developing a more secure future for ordinary working people in this country."

Meantime, she appears set to include her Brexit negotiating priorities in the Conservative manifesto to lock Remain-backing Tory MPs and the House of Lords into backing her stance.

The manifesto will include guarantees to end the free movement of EU citizens, to leave the European single market, and to end the jurisdiction of the European Court of Justice.

Including the pledges in the manifesto would make it extremely difficult for Remain-backing Tory MPs to rebel on the issues in Commons votes if the party won the snap election and as the Brexit talks go on.

Moreover, Peers would also be forced to back the priorities under the so-called Salisbury Convention, which states the Lords should not try and vote down government plans mentioned in an election manifesto.

Elsewhere, Mrs May is also coming under pressure from within her party to ditch promises made in Mr Cameron's 2015 election manifesto, such as the commitment to spend 0.7 per cent of national income on foreign aid.

But Ruth Davidson, the Scottish Conservative leader, pledged her own absolute commitment to it, saying: “International aid not only benefits…the countries that receive it but we benefit too. It takes moral courage to be one of the leading countries that espouses that, when there are a lot of countries that don't do it."

Bill Gates, the philanthropist and Microsoft co-founder, has also urged the PM to stick to the target, which was put into law with the backing of the Tory-Liberal Democrat coalition in 2015.

Downing Street refused to comment on the manifesto before it is published.