An ex-marine and serving bodyguard to the Queen has been left “angry and frustrated” after his French wife of 24 years was left fearing for her future right to stay in the UK.

Simon Milne MBE, 58, now chief executive of the Royal Botanic Garden Edinburgh, has served in Northern Ireland and Bosnia and is one of 27 Gentlemen at Arms who guard the Queen on royal occasions.

His wife Francoise, 50, applied for a permanent residency card after the Government “failed to clarify” the future rights of EU nationals living in the UK.

Mrs Milne, who lives in Edinburgh with her three children and husband, said her application was refused in October as she could not prove she was “self-sufficient”, adding she has been left “scared and confused” about the future.

The couple’s MP, the SNP’s Deidre Brock (Edinburgh North and Leith), has written to ministers and raised their case in a Commons debate last week.

Mr Milne said he finds the decision “extraordinary”.

He said: “With the uncertainty around Brexit at the moment my wife decided to apply for permanent residency.

“She has supported me through my career with the Royal Marines and now in my current role.

“I am flabbergasted with this decision, I am angry and frustrated. I can only hope that it is an unintended oversight.”

Mrs Milne said her “world has been shattered” by the Brexit vote.

She said: “It felt like I had been cut in half when the vote came back yes, my children were crying.

“I never felt I needed to claim dual nationality before, I could move about freely and work freely, now it feels like a lot of freedom has gone.”

Mr s Milne said she was refused a residency card because she could not prove she was “self-sufficient”. She said: “I do a little bit of upholstery, I never make enough to support myself and rely on my husband.

“They will not take into account that I am married to a British man, that is irrelevant, it’s hard to believe.

“I don’t know what will happen after 2019. I don’t know if there will be time limits on how long I can stay in the country, if I want to leave to see my parents in France. I don’t know what the rules will be on coming back.

“I have participated in British society, I have raised three intelligent lovely children, I have voted, I have worked, I am, I have been a citizen.”

Ms Brock said: “The Government says EU nationals shouldn’t worry, then refuses residency to long-term citizens like Francoise. What an appalling way to treat people, making them feel unwelcome in their own homes.”

A Home Office spokesman said: “The rights of EU nationals living in the UK remain unchanged. EU citizens who have made their lives in the UK have made a huge contribution to our country and we want them and their families to stay.”