MPs have lambasted Theresa May’s proposed £35,000 pay threshold for skilled migrant workers as a “ludicrous” and “simplistic measure” during a Parliamentary debate scrutinising the divisive change to immigration rules.

The debate was held at Westminster Hall on Monday after more than 100,000 people signed an online petition against the measure, which could lead to thousands of teachers, charity workers and NHS staff being deported from the UK if they fail to meet certain financial requirements.

Many of those in attendance raised concerns over the security of the nursing profession's place on a list of occupations exempt from the thresholds.

Tier II skilled workers in Shortage Occupations will be exempt from the threshold, and nurses have been provisionally placed on the Shortage Occupation list, pending review by the Migration Advisory Committee (MAC).

However, SNP MP Stuart McDonald raised concerns about how long nursing would remain on the list in light of a recent increase in the number of non-EU people entering the profession.

“If removed from the Shortage Occupation list this labour would be lost”, Mr McDonald told the debate, adding this “worrying stop gap answer for the NHS is not sufficient”.

Labour’s Keir Starmer also addressed the concerns saying the threshold could lead to “very serious skill shortages for our economy.”

The SNP’s Kirsten Oswald, who called the measure "simplistic" and "crude", queried how long nursing would remain on the exemption list, also commenting there had been “nothing said to the teaching profession” regarding exemptions.

Monday’s debate was the first time MPs were able to analyse the £35,000 threshold for non-EU workers, which was pushed through without a Commons vote in 2012.

It is due to come into effect next month and will mean overseas workers who have lived in the UK for five years must prove they will be paid the new minimum threshold of £35,000 in order to stay in the country.

Other concerns raised in the debate included fears the threshold did not take into account varying wage levels across the UK, with Ms Oswald pointing out those working in London were often paid higher salaries than those in other parts of the country.

Tommy Sheppard, SNP MP for Edinburgh East, said the "ludicrous" measure did not take into account “regional variations in the UK” and would “further imbalance the UK economy”.

Ms May was criticised for failing to attend the debate, instead sending junior minister Richard Harrington in her absence.

Many condemned the lack of MPs present at Westminster Hall, which was attended by seven SNP MPS, three Tory MPS and two Labour MPS.

The Stop35k campaign, whose members set up the original petition on the Government website, said in a statement following the debate: “We urge the Government to reconsider the implementation next month, and give the MAC an opportunity to complete a thorough assessment of suitable pay thresholds across jobs and geography in the UK.