Sir Keir, who was appearing in front of MPs on the Liaison Committee, said: “It’s irresponsible at any time, particularly at the moment.
“It comes on the back of a very substantial pay increase in the last year or so.
“There’s a deal that we’ve put on the table that could have been taken forward, and so I think it’s irresponsible action by the BMA, and not for the first time.”
The offer did not include any promises on pay – Health Secretary Wes Streeting has maintained he will not negotiate on that after resident doctors pay has been increased by nearly 30% in the past three years.
The BMA argues that, despite the pay rises, resident doctors’ pay is still a fifth lower than it was in 2008, once inflation is taken into account.
Streeting said the pay demands were “fantasy”.
And he added: “The BMA has chosen Christmas strikes to inflict damage on the NHS at the moment of maximum danger. These strikes are self-indulgent, irresponsible and dangerous.”
He said he hoped resident doctors would still go to work, saying there was a different magnitude of risk striking at this moment.
