The feud between Ben Wallace and his junior minister Johnny Mercer escalated dramatically today - with the latter's wife even getting involved.

The Defence Secretary renewed the bitter spat saying it was 'lucky' Johnny Mercer did not have to run the department's budget.

In an interview with LBC, Mr Wallace pointed out that he was in charge of 224,000 staff while the veterans' minister had '12 people in the office'. 

The brutal rebuke prompted Felicity Cornelius-Mercer to tweet her shock at the 'disdain' Mr Wallace was showing for her husband and his brief. 

It came after Mr Mercer insisted it was 'not credible' for Mr Wallace to say the UK's armed forces had been 'hollowed out'.

Mr Mercer - a former commando captain - suggested his boss had been making overblown statements to as part of wrangling with the Treasury ahead of the Budget on March 15.

Asked about Mr Mercer's comments, Mr Walllace said: 'Well, I think, you know, Johnny is a junior Minister. 

'And Johnny luckily doesn't have to run the budget. You know, I have a defence budget that has to deal, like all the other budgets, with inflation, with changes to threat, and I have to just deal with that. And that's my job.'

Asked if Mr Mercer was 'being naive'. Mr Wallace said: No, no, no. I just think, you know, his experience is not… he's not the Secretary of State. 

'He hasn't run… I run a Department of 224,000 people I think it is. or something like that.'

When he was pressed on how many staff Mr Mercer was in charge of, Mr Wallace repled: 'He's got 12 people in the office.'

Ms Cornelius-Mercer posted on Twitter saying 'wow' with a shocked emoji. 'The disdain from @BenWallaceMP for @JohnnyMercerUK and his office for veterans affairs really is something else.. you may start to realise why care for veterans is such a daily battle,' she said.

It is far from the first staunch intervention on her husband's behalf. After Mr Mercer was sacked by Liz Truss in September, Ms Cornelius-Mercer said the Cabinet system 'stinks' and 'treats people appallingly'. 

She tweeted a picture mocking Ms Truss as Beaker, a character from The Muppets television show, and giving an account of Mr Mercer's exit discussions. 

Ms Cornelius-Mercer tweeted: 'He asked her 'why would you do this, who is going to be better at this role than me, which of your mates gets the job, you promised a meritocracy?'

'PM - I can't answer that Johnny.

'This system stinks & treats people appallingly. Best person I know sacked by an imbecile @trussliz.'

She added in a follow-up Tweet, 'Yes I am feeling bitter. Please allow it - 24hrs then back to positives'.

During a debate last month in the Commons, former Scots Guard Mr Wallace said he was 'happy to say that we have been hollowed out and underfunded'.

Only days later, he told a joint UK-Australia press conference in Portsmouth that a 'growing proportion' of Government spending would need to go towards keeping the country safe, in a message that was read as being directed at Chancellor Jeremy Hunt ahead of the Budget.

It comes against a backdrop of UK efforts to support Ukraine in pushing back invading Russian troops and rising global tensions with China.

Reports have suggested Mr Mercer had taken umbrage with the Defence Secretary's remarks in Parliament, apparently telling a Coalition for Global Prosperity event they were 'patently not true'.

The Cabinet Office minister, asked about his reported past criticism of Mr Wallace's stance, told LBC: 'Ben is engaged in a lobbying effort for his department, as you would expect him to be.

'The facts are that when I came into politics, defence spending was around £38 billion per year — it is just shy of £50 billion a year now.

'It is obviously not credible to say that the money has been taken out of defence.'

Pressed on Mr Wallace's handling of the MoD funding debate, Mr Mercer added: 'I think he is advocating for his department when a spend is coming up.

'But when this Prime Minister was chancellor only 18 months ago, he gave the biggest settlement to defence since the end of the Cold War.

'So it is then not credible to go forward and say that we haven't put money into defence.

'I think we have, I think our MoD and military is in terrific shape. There is lots to be positive about, so I'm afraid I don't really buy into the narrative of running down defence.'

The comments come ahead of an update to the Integrated Review of Security, Defence, Development and Foreign Policy, which is expected in the coming weeks.

Published in 2021, the integrated review announced a foreign policy 'tilt' towards the Indo-Pacific in recognition of China's growing influence in the region.