Image copyright Unknown Image caption News of homeless ex-soldier Darren Greenfield's death was shared on social media

The sister of a homeless ex-soldier who died while sleeping rough in Edinburgh said she tried to help him but he was not ready to leave the streets.

Darren Greenfield had served with the Royal Tank Regiment but struggled to cope after leaving the Army.

He had become well-known in Edinburgh, begging for change while wearing his khakis near Waverley Station.

His death before Christmas, at the age of 47 after contracting an infection, sparked outrage on social media.

Many questioned how someone who served their country could end up destitute on the streets.

Darren's sister Aston Robertson told BBC Scotland's Stephen Jardine programme he was "my hero".

She said her brother, who was educated at a private school in Berkshire, was "very knowledgeable".

"He was a lovely man. He was everything to me," she said.

Tracked down

Darren, who was also known as Dan, had driven armoured vehicles and tanks while serving on tour in Bosnia in the late 1990s.

His sister said she felt his time in Bosnia was "the downfall for him" and he suffered from PTSD (post-traumatic stress disorder) as a result.

After he left the Army his family did not see him for 15 years, she said.

But her younger sister, who lives in Sunderland, tracked him down and they went to meet him in London.

Image copyright facebook Image caption Darren had a cardboard sign saying "Soldier in need"

Aston persuaded Darren to move to Edinburgh and secured a room in a residence for ex-soldiers at Whitefoord House in the city.

She said that the daily routine at Whitefoord House was very structured and did not suit Darren.

"I feel that he did not want to be regimented any more," she said.

His sister told the programme she had been going to work one day when she saw Darren on the streets.

Aston said he promised it was temporary and refused offers of help.

However, Darren became a regular fixture outside the station with a cardboard sign bearing his service number and the message: 'Soldier in need, please help, thank you God bless.'

'It was heart-breaking'

His sister said: "He knew where I worked and he knew I was going to see him.

"I don't know if that was a cry for help. I did try as much as I possibly could."

She said she invited him to her flat but he never turned up.

If he had got help in the beginning it would have been a lot better Aston Robertson, Darren's sister

"It was heart-breaking," she said.

"I felt helpless. I felt like I could not do anything."

According to Aston, Darren was not given any support when he left the armed forces in his late 20s.

"I feel the damage was already done," she says.

"If he had got help in the beginning it would have been a lot better."

On 17 December last year, doctors got in touch with Aston's sister, who shared the same surname as Darren.

She contacted Aston to tell her that Darren was in hospital with an infection.

"I got the phone call at work and rushed to the hospital," she said.

"When I got there he was non-responsive. He had had a stroke and they told me I had a couple of hours to say my goodbyes."

'Very troubled'

Walter Hamilton, a volunteer with Soldiers Off The Streets, told the programme he met Darren on four occasions.

He said: "We tried to re-home him. The very last time he was ready to come off the street. He was ready to be re-homed."

But Darren's sudden illness prevented that happening.

Walter says: "If someone has got a limb missing you can see it.

"If someone is suffering from PTSD you can't see the injury.

"Darren must have been very troubled."