The 23 year old keeper has agreed terms to sign from Leyton Orient, where he graduated from the Youth team to make a number of professional appearances.

The goalkeeper, who made his England under-18’s debut back in March 2014 against Croatia, has been on the substitutes bench on a number of occasions over the past few seasons.

The highly-rated youngster, enjoyed a number of loan spells at the likes of Histon and Farnborough.

Grainger made his first-team debut for Leyton Orient at Luton Town in the Johnstone’s Paint Trophy on September 1, 2015, before making his league debut against Exeter City four days later.