Ask Central hit a 52-week high of 186.5p yesterday as 2.4m shares, or 2.6% of the equity, changed hands after rumours that another private equity group, possibly working with Luke Johnson, the former chairman of PizzaExpress, could be thinking of making an offer for the company. The planned merger between Ask, owner of the Ask and Zizzi's chains, and City Centre Restaurants, which runs Frankie & Bennie's and Caffe Uno, to make a new company called The Restaurant Group has already hit bumpy ground after TDR Capital, the current co-owner of PizzaExpress, said last week it might counter City Centre's recommended offer. Observers believe TDR's intervention was spurred by fears that a merged Ask/City Centre, with all the opportunities for rolling out Ask's pizza chains into some of City Centre's underperforming outlets that would occur, could provide significantly increased competition to PizzaExpress, which TDR acquired last year in partnership with Capricorn, owner of the Nando's brand. City Centre is offering 66p and 1.54 of its shares for every Ask share, which, together with a 2.85p dividend entitlement, made its offer worth 183.6p per Ask share at close of play yesterday. Greg Feehely, leisure analyst at the City firm Altium Capital, said TDR's intervention meant "at the very least" the likelihood has increased that City Centre will have to improve its terms. The strategic logic for a merger between City Centre remained strong, he said, and City Centre will be loath to lose out to TDR.