ALL six Scottish Tory MPs backed Boris Johnson's plan to increase National Insurance (NI) payments as it passed a vote in the House of Commons

MPs voted to approve a 1.25% increase to National Insurance with 319 votes in favour and 248 against.

The Tory government’s working majority of more than 80 was reduced to 71, with a number of Conservatives apparently choosing to abstain while others made clear they were only voting with the greatest reluctance.

It reflected the concern within the Tory ranks that Johnson was not only abandoning a manifesto promise not to raise the main rates of taxes but that he was taking the tax burden to record peacetime levels.

READ MORE: 'At long last grow a backbone' and stand up to Boris Johnson, Douglas Ross told

Scotland's six Tory MPs voted in favour of the proposal including Scottish Tory leader Douglas Ross, Scotland Secretary Alister Jack, Scotland Office minister David Duguid, John Lamont, David Mundell and Andrew Bowie.

Five Tory MPs rebelled to oppose the Government’s NHS and social care tax rise plan, according to the division list.

They were Christopher Chope (Christchurch), Philip Davies (Shipley), Neil Hudson (Penrith and The Border), Esther McVey (Tatton) and Sir John Redwood (Wokingham).

Another 37 Tory MPs did not record a vote. This does not automatically mean they abstained from the vote as they may have been given permission to miss the vote.

The National:

WATCH: Boris Johnson told 'keep your mitts off' Scotland's NHS amid tax hike row 

The SNP’s shadow chancellor Alison Thewliss MP (above) said: “The Tory government’s regressive tax increase will unfairly burden millions of Scottish families, young people, and the low paid, and leave them worse off.

“The move also risks Scotland being sold short and receiving less in return than the money taken from Scottish-based National Insurance payers.

"Everyone supports investing more money into our NHS but this tax rise is regressive and, coupled with the premature withdrawal of key Covid income support schemes and the scrapping of £20 UC uplift, signals yet another round of Tory austerity.

"At a time when we should be strengthening support and building a strong recovery from the pandemic, the Westminster Tory government is instead holding back a fair and equal recovery from the crisis.

"It's beyond any doubt that the only way to protect Scotland from Tory cuts and regressive tax hikes is to become an independent country."

READ MORE: Five times Boris Johnson's government claimed it wouldn't raise taxes

Previously today, Thewliss called on the Scottish Tory MPs at Westminster to "at long last find a backbone and vote against these tax plans" but it seems that her fear that they would once again “rubber-stamp Boris Johnson's harmful policies” was realised.

Before the vote, Boris Johnson spent almost an hour addressing a private meeting of Tory MPs.

told the backbench 1922 Committee that the Conservatives remained the party of free enterprise, the private sector and “low taxation”.

“We should never forget that,” he said.

Labour’s amendment calling for Chancellor Rishi Sunak to publish an impact assessment of the national insurance increase was rejected by 335 votes to 243, majority 92.

The Opposition had asked for Sunak to detail before April 2022 how the tax hike would affect jobs and businesses, and also the distributional impact of the measures on different income groups and regions.