Chris Robshaw has expressed his "deepest apologies" after he was among the Barbarians players who breached coronavirus protocols, resulting in Sunday's clash with England being cancelled.

Former England captain Robshaw was due to make his final appearance in his homeland at Twickenham this weekend before joining Major League Rugby side San Diego Legion.

The Quilter Cup contest will not go ahead, though, after Harlequins legend Robshaw was one of a number - reportedly a dozen - of Baa-Baas players to breach strict regulations.

An investigation was launched by the Rugby Football Union (RFU) after members of the squad left the team hotel without permission or informing organisers about their whereabouts on Wednesday. 

The players in question were separated from the rest of the group in the bubble upon their return. 

It was then confirmed by the RFU on Friday that an earlier undisclosed breach of the COVID-19 rules took place on Tuesday, with Barbarians players leaving the hotel without permission and not isolating from team-mates after they returned. 

The RFU stated it had no alternative but to call the contest off.

Robshaw held his hands up in a remorseful twitter post, writing: "I want to express my deepest apologies for breaching Barbarians COVID-19 restrictions by leaving the hotel post-training with some of my team-mates.

"A huge effort went into conducting this match in a safe fashion and it was irresponsible of me to break the protocols which are put in place to protect players, staff and the public

"I understand that my actions have ultimately contributed to the cancellation of Sunday's match and I am sincerely remorseful for my role in undoing all the amazing work that went into trying to make it happen. I promise that I will learn from this mistake and ensure something like this never happens again."

The match was due to give England some playing time a week before they face Italy in a decisive final Six Nations match against Italy in Rome.

England's 2003 World Cup-winning coach Clive Woodward was left in "disbelief" at the behaviour of the players.

"I'm sure they're feeling incredibly stupid and incredibly embarrassed. It's just stupidity, they've been ridiculously stupid," Woodward told talkSPORT. 

"My reaction was just kind of gobsmacked really. These are professional players and they know what's at stake. It's live on TV, it's a game that everyone was looking forward to. 

"I can't believe they've been so naive and stupid to think they can get away with it. People could see them, they're well-known people. I just shake my head in disbelief."