Defence minister Luke Pollard has said he was “disgusted” when he heard that soldiers were injured while using Ajax armoured vehicles, which he had previously been assured were safe.

Last month, the Army paused its use of the vehicles after 30 soldiers became ill from noise and vibration during a military exercise.

The £6.3bn Ajax project had been due to deliver 589 armoured vehicles with the first entering service in 2017. However, the programme has been beset by problems and repeatedly delayed.

Speaking in the House of Commons, Pollard said three investigations were under way and promised to take “whatever decisions are required to end the saga one way or another”.

He later added that the Ajax vehicle had completed “42,000 km of testing without such injuries” and that “not all the vehicles on that exercise caused injuries”.

Shadow Conservative defence secretary James Cartlidge said the incidents with noise and vibration “sound strikingly similar to the problems that I was assured, as minister for defence procurement, had been resolved”.

“I imagine the minister is as furious as I am at having been repeatedly given what now turn out to be false assurances by those responsible for the Ajax programme,” he said, adding: “Surely he is left with a binary choice – fix it or fail it.”

Cartlidge also raised “a disgraceful incident” where an employee of General Dynamics, the company making Ajax, had “belittled the injured soldiers” in social media posts according to reports.

Pollard confirmed that General Dynamics had apologised in writing to the Ministry of Defence for the messages.

In a response to the Times newspaper last week, General Dynamics said it had launched an investigation into the remarks and they “do not reflect those of the company in any way nor do they align with our core values”.

The British Army ordered the new Ajax vehicle in 2014 to replace the ageing fleet of CVR(T) vehicles which were first used in 1971.

The Ajax vehicles were due to come into service by 2017 but their delivery has been delayed.

So far around 160 of the intended 589 have been built however, the programme is not expected to reach full operating capacity for another four years.

A review of the process in 2023 said there had been “systemic and institutional” failures and that some of those working on the programme had been “infected” by “optimism bias”.

In 2023, then-Defence Secretary Ben Wallace said he believed Ajax had “turned the corner” and in early November, Pollard said it had “left its troubles behind”.

However, in late November the government confirmed that a training exercise had to be stopped after 30 service personnel operating Ajax reported “noise and vibration symptoms”.

The Times reported that some soldiers were vomiting while others were shaking violently.

At the start of December, Pollard said he had received written assurances from the chief of the defence staff and the then-national armaments director that Ajax was safe.

Responding to an urgent question in Parliament on Monday evening, Pollard said he wanted to get “to the bottom” of what had happened.

He said he had ordered a ministerial review alongside two other investigations being carried out by the Defence Accident Investigation Branch and the Army Safety Investigation Team.

He told MPs: “The safety of our people remains the top priority for me and the ministerial team. As such, we will take whatever decisions are required to end the saga one way or another.”

The Labour chair of the parliamentary defence committee Tan Dhesi said the events were “an absolute shambles” and expressed concern about the Army’s readiness “at a time of such increased international tensions”.

The Liberal Democrats’ defence spokesman James MacCleary urged the government to provide contingency plans “should Ajax be deemed unsafe or unviable”.

The vehicles are made in South Wales. Newport West and Islwyn Labour MP Ruth Jones, noting that Christmas is “fast approaching”, asked if the minister could give assurances that the jobs in her constituency linked to the programme were “safe for the long term”.

Pollard did not offer an assurance but said he recognised “the importance of the economic contribution that GD [General Dynamics] makes not just to Merthyr but to the wider community”.

Conservative Sir Julian Lewis expressed his concern that if the government made the decision not to go ahead with Ajax, there would be “a huge stand-off between the MoD and the company as to who is responsible for picking up the bill”.

“Has thought been given to sharpening the pencils of the MoD lawyers,” he asked.

Pollard said he would not “speculate” until his review was completed but added: “The defence secretary and I are clear about the fact that all options remain on the table.”

General Dynamics have been approached for comment.