New on the menu: Subway sandwich chain explores potential sale

Franchise company, with more than 37,000 restaurants in over 100 countries, could be valued at more than $10bn

Fast-food chain Subway has put itself on the menu - announcing on Tuesday it is exploring a possible sale of its business after 58 years of family control.

After years of rapid growth, rising costs and mounting competition from rivals have taken their toll on the company in recent years, but it still has more than 37,000 restaurants in over 100 countries - making it one of the largest chains in the world.