The 54-year-old, who was rushed to Whittington Hospital, received help from staff and customers from a local shop.
"It was quite dramatic for us all to witness it," Nicky Campbell, who works in the shop near to where Sansom collapsed, told the Daily Mail.
"We were all running around like headless chickens trying to help. We wish him all the best. We would love him to pop in and tell us he's all right."
Sansom, who spent eight years at Arsenal during his playing days, leads tours around the Emirates for the Premier League club.