John Hopkinson was forced to leave the army after a major fall damaged his foot more than a year ago. He has been job-hunting ever since.
The 40-year-old had just been visiting the Jobcentre, in Arundel Street, Landport, when he was involved in a car crash.
The former corporal was taken to hospital and released after treatment which left his leg in a cast.
The following day he hobbled to the centre, still determined to hunt for a job.
But when Mr Hopkinson asked a G4S security guard if he could have a seat on which to rest he was told no and was instead told to sit on the floor if he needed to – something that infuriated the ex-soldier.
The veteran’s treatment has since outraged Portsmouth South MP Flick Drummond.
‘I felt like a lower-class citizen – it was appalling,’ added Mr Hopkinson, who served for 15 years with the 1st Battalion The Princess of Wales’s Royal Regiment.
‘I was in a world of hurt – I couldn’t walk properly because of my foot and I couldn’t stand without being in constant pain.
‘There were several chairs that looked available and I asked if I could have one brought over.
‘I was told that wasn’t possible and that I could sit on the floor. I couldn’t believe it. I was furious.’
Mr Hopkinson, who lives in Southsea, was still recovering from a major operation on his foot to repair the damage he suffered in his fall.
After pleading with the security officer for several minutes, the widower was eventually given a seat.
Portsmouth South MP Flick Drummond says she is shocked by his treatment.
The Tory MP said she would visit the site and speak to staff.
She added: ‘This is the whole point of the Armed Forces Covenant – they put their lives on the line for us so we should do everything we can to help them.
‘I’m appalled at the treatment this veteran has received.
‘There should be seats there anyway.
‘There will be a lot of people there with disabilities who need to be looked after.’
A spokeswoman for the security firm said the guard’s behaviour was ‘out of character’ and that an investigation was to take place.
Craig Price, G4S secure solutions operations director, added: ‘I am grateful to the member of the public who came forward to report this incident and we are looking into this case.’