Sky Sports was last night under growing pressure to axe its main football anchor Richard Keys, after earlier sacking his colleague Andy Gray over a string of sexist remarks made off air but caught on tape.

After Gray was summarily dismissed when new footage came to light that showed him making lewd suggestions to a female co-host, the pressure to take action against Keys, too, increased when yet another clip appeared to show him talking in sexist terms about a former girlfriend of the pundit Jamie Redknapp.

The pair were originally disciplined for making sexist remarks about the female assistant referee Sian Massey before Saturday's match between Wolves and Liverpool. Again they were off air but recorded on tape and leaked to the media.

The new evidence against Keys, in which he refers to the woman as "it" and twice asks the former Liverpool and Spurs player if he "smashed it", appeared to come from the same source as the earlier Gray video and was posted from the same YouTube account. In it Keys is recorded chatting to Redknapp, Ruud Gullit and Graeme Souness before going on air at Stamford Bridge. The conversation begins with someone behind the camera mentioning a former girlfriend of Redknapp called Louise. Keys asks Redknapp whether he "smashed it" and the former player replies that he "used to go out with her".

As Gullit fiddles with his phone and Souness tries to interject, Keys returns to the question. "Mind you, that's a stupid question, if you were anywhere near it, you definitely smashed it. You could have gone round there any night and found Redknapp hanging out the back of it," he says, laughing. Sky Sports said it was unable to comment on the new footage, which was later removed and the original account from which it was posted closed, but is expected to examine it further today. It may seek to argue that the two cases are different.

Gray's lawyers last night confirmed that they had been instructed to act for him over his sacking. Schillings, also acting for Gray in his phone hacking action against the News of the World, said in a statement: "We have been instructed by Andy Gray in relation to the termination of his contract by BSkyB. Whilst there have been a number of media inquiries made in relation to this matter, it would be inappropriate for our client to comment at this time." Gray was sacked for "unacceptable and offensive behaviour", according to Sky, after new evidence came to light of him making suggestive remarks to a female co-presenter.

The broadcaster could not explain why Gray had been dismissed while Keys and the touchline reporter Andy Burton were still employed, despite similar offences. Sky said Gray had been sacked after new evidence relating to an off-air incident that took place in December 2010 "came to light after Andy Gray had already been subjected to disciplinary action for his comments of 22 January 2011".

The fresh evidence emerged after a video was posted on YouTube that showed him asking his fellow presenter Charlotte Jackson to "tuck this in for me, love" as he gestured towards his trousers during a commercial break. "Andy Gray's contract has been terminated for unacceptable behaviour. After issuing a warning yesterday we have no hesitation in taking this action after becoming aware of new information today," said Sky Sports' managing director, Barney Francis.

Gray, who helped make the broadcaster into one of the most powerful forces in sport on the back of its multi-billion pound Premier League rights deals, was last night facing the prospect of seeing his career unravel. Betfair, the online betting exchange which pays Gray a substantial sum to appear in its advertising, said earlier in the day that, while it would not tolerate sexism, it had "no plans to change" its relationship with Gray. But immediately following his sacking Betfair said: "Inlight of the latest developments we are reviewing the situation."

Gray was initially hauled off air on Monday after he and Keys were caught on tape making derogatory comments about Massey. Speculation last night centred on who leaked the offending clips. Insiders said the most likely explanation was that disgruntled colleagues had systematically leaked the footage to seal Gray's fate.

Massey was last night stood down from her planned engagement to run the line for Crewe Alexandra's match with Bradford for fear that it would place her at the centre of a media circus.