Television dramas including the political thriller Bodyguard can damage the reputation of veterans' mental health, a Defence Minister has warned, as he said the forces must retain tier-one capabilities after Brexit.

Tobias Ellwood criticised the portrayal of ex-service personnel in the hit BBC One series, in which Richard Madden played a former soldier with psychological scars who becomes the Home Secretary's protection officer.

The minister, opening a Commons debate on the Veterans Strategy, said: "Some of the things that we see on TV - the Bodyguard is the latest - which gives you this impression that somehow if you do serve you somehow might be mentally affected.

"Now what does that do to the reputation of the Armed Forces? What does it do to a potential recruit - seeing that and getting that idea that somehow you might be affected if you join the Armed Forces? It would actually hinder you from signing up.

"What does it do to an employer that doesn't have exposure or a knowledge of what it's like being in the Armed Forces? It will actually perhaps prohibit you, it will bias you against signing somebody up with armed military experience."

Mr Ellwood also called for Britain to continue to play a "pivotal role on the international stage" after Brexit, regardless of the eventual relationship the UK has with the EU.

He told MPs: "Whatever ID card we end up having in our back pockets, we must remain a nation with tier-one capabilities - with that full spectrum defence posture, able to protect our people, able to defend our interests and of course able to promote prosperity."

Mr Ellwood said he hoped the House would support the case for a "very strong defence capability" in the forthcoming spending review.

Shadow defence secretary Nia Griffith was particularly critical of increasing numbers of homeless people, many of whom are veterans.

The Labour MP for Llanelli said: "It's truly shameful that anyone who has served this country should find himself or herself on the streets.

"This Conservative Government must take responsibility for its failure to deal with the problem.

"Rough sleeping has doubled since 2010 and homelessness is a direct consequence of this Government's decisions on housing and welfare reform and its unprecedented cuts to local budgets and charities."

Conservative Mark Francois, a former defence minister, warned of shortcomings in treatment for physical war wounds, despite a new Centre for Conflict Wound Research opening this week in Birmingham.

He said: "The case was underpinned by the promise of closer NHS and defence service collaboration so that military and civilian patients and researchers could benefit holistically from complex trauma experience.

"However, the NHS has not fully engaged with the same enthusiasm as the military meaning the original vision is falling short.

"I would ask the Minister to liaise with his colleagues in the Department for Health to see if something can be done to put this right, because the more we learn about treating wounds like this the better we become at dealing with prosthetics and the more we will benefit civilians as well as veterans."

Mr Francois also raised the issue of delayed treatment for those with diagnosed mental illness, which he said meant veterans were waiting "almost a year" to receive appropriate treatment in parts of Wales and Northern Ireland.

He added: "For those who have served their country in uniform this is completely and utterly unacceptable."