The 54-year-old, who made 86 appearances for the Three Lions between 1979 and 1988 and played at the World Cup twice, told The Sun how he had struggled with personal problems which had hampered him for several years.
"I have been living homeless for 10 days, that's because I've got no money, I'm a drunk, I'm not feeling very well and I'm a gambler. I've been living on the street," he said.
"I am just a drunk. I drink as much as I can get."
The Professional Footballers' Association and his former club Arsenal have offered their support to Sansom, who had been staying with his sister Mary until recently.
"I am in a bad way. Arsenal are trying to help me, but I have got to try to help myself," he said.
Sansom made his professional debut for Crystal Palace at the age of 16 and went on to captain the England Under-21s before becoming a permanent fixture in the senior team's defence.
The full-back spent eight years at Arsenal, playing 314 matches, before leaving to join Newcastle in 1988, followed by spells at QPR, Coventry, Everton, Brentford and Watford before retiring.
Since then, Sansom had worked in the media and undergone several rehabilitation programmes.
Source: PA
Source: PA