The Thomas Cook Group, the Co-operative Group and the Midlands Co-operative are to merge after the Competition Commission gave the go-ahead for the deal.The merger brings together two of the three largest travel agents on the UK highstreet.Thomas Cook currently has 780 stores, Co-op 360 and Midlands 100.There were fears the acquisition would see the new group dominating high street and online travel agencies.But in its final report published today, the Competition Commission concluded that the tie-up "will not result in a substantial lessening of competition in any markets in the UK, in particular for customers buying package holidays from high street travel agents". "Therefore, customers are unlikely to suffer from significantly higher prices or reduced choice as a result of the joint venture," it said.Thomas Cook will continue to conduct its tour operator business separately from the joint venture.Thomas Cook has been struggling recently and said in July its third quarter results will miss expectations as the turmoil in the Arab world and economic weakness in the UK continue to take their toll.Last week it announced its chief executive Manny Fontenla-Novoa would step down immediately and appointed deputy head Sam Weihagen to temporarily take charge of the company.