Allison rejoins Bath
The 29-year-old joined Bath from London Irish in November on a short-term loan and will return to his parent club until the end of the season, before heading back to the West Country for pre-season training.
Allinson impressed with his game management during his spell with the Club and will bring invaluable experience in the number nine shirt from next season.
On signing fresh terms with Bath, Allinson said: "I’m really excited to be returning to Bath next year and I’m looking forward to getting a solid pre-season under my belt before the start of the new campaign.
"There is a great deal of competition and experience in the number nine shirt and that is something that brings the very best out of me as a player. The team is showing it can compete with the best and to be here for the next two years challenging for honours, it can’t get any better for me,"
Director of Rugby, Todd Blackadder, added: "We are delighted to have secured the services of a number of first team players recently and to add Darren to that list is really pleasing.
"He is an experienced player and a calming influence on and off the field, which will be invaluable over the next few seasons,"
