Desperate defence chiefs are testing rubber tracks on the £6.3billion Ajax armoured vehicle – after another soldier was injured during trials.

Ajax faces the axe, resulting in a huge write-off for taxpayers, unless a solution can be found quickly to its vibration and noise issues.

The vehicle should have entered service in 2017 but has been plagued by problems, prompting former defence secretary Ben Wallace to call it 'a ridiculous project'.

The Daily Mail has learned that senior officers are considering changing its tracks – in what could be the last attempt to save Ajax.

Standard steel tracks have contributed to scores of soldiers developing hearing loss and health problems caused by excessive vibration that have ended their careers. Some have ended up with 'white finger' – a painful nerve and blood vessel disorder caused by vibration.

Now the Army is experimenting with a composite rubber track (CRT) known as 'Blackjax'. A CRT is a continuous band of rubber reinforced with steel cords and carbon tubes. It is lighter and reduces noise and vibration and can improve fuel economy.

CRTs have been fitted successfully to armoured vehicles used by other nations, including the Norwegian CV90 and the Australian Redback vehicle. Remarkably, rubber tracks were recommended by a whistleblower when Ajax was experiencing development issues in 2019 but were rejected as too costly. 

But, with top brass facing the prospect of writing off billions of pounds of public money, rubber tracks are being looked at again.

Procurement minister Luke Pollard last week confirmed tests with steel tracks were stopped after another soldier suffered vibration issues. Last month, in separate trials, around 30 soldiers became ill on training exercises involving Ajax in Dorset.

In a written statement to Parliament, Mr Pollard said: 'This additional report of an injury is a serious concern to me so, out of an abundance of caution, and to ensure safety of personnel, I have directed a pause on Ajax trials.'

Tory Armed Forces spokesman Mark Francois said: 'We clearly cannot continue like this. The imperative is for ministers to either fix Ajax or fail it.'

There are four separate government investigations into Ajax to assess its viability. Mr Pollard has also held crisis talks with the vehicle's manufacturer, General Dynamics UK.

The Ministry of Defence declined to comment officially on the testing of rubber tracks. The tests were confirmed by defence sources.