Martin Robinson was a business contact of Frank Foster. The two had a dinner and Frank's calculating mother Anne Foster reminded him that Martin had just split from his wife of twenty years and now would be a good team to give him a shoulder to cry on - and then get a 20% on the price.
Martin was meeting Frank at Alonso's Restaurant and when he turned up there he was surprised to see Carla Connor at one of the tables. Frank was awaiting trial on the charge of raping Carla though Martin thought their business split was over something trivial and asked if they had now sorted things out. Hearing that Frank was on the way, Carla fled the restaurant where she had been waiting for Peter Barlow to arrive. She found him outside in his car and told him to get away quickly but Frank had also recently arrived and saw the couple together, giving him proof of the affair that the two were conducting that he was able to use to discredit Carla at his trial.