Labour has accused the government of a "catastrophic misstep" by failing to stop travel from India to prevent the spread of a new more virulent Covid variant.
Shadow health secretary Jonathan Ashworth said the UK had borders "about as secure as a sieve" and accused Matt Hancock of ignoring a warning a month ago.
The government has been accused of being slow to impose travel restrictions on India so that they would not overshadow a planned travel visit by Boris Johnson to the country.
But the visit was ultimately cancelled after the south Asian country faced a huge wave of Covid and mass mortality on the back of a new variant.
"Yesterday, he warned on the television, that the B-1617.2 variant could spread like wildfire amongst the unvaccinated. But does he accept, we could have avoided this?" Mr Ashworth asked the Health Secretary during an exchange in the Commons.
"Our borders have been about as secure as a sieve. The delay in adding India to the Red List, surely now stands as a catastrophic, misstep."
Mr Ashworth said that "one month ago in this house I urged him to act quickly in response to this variant".
He noted that data from the Sanger Institute released today "shows rapid increase in this variant" to 30 per cent of all sequenced cases in the UK, excluding travel and surge testing cases.
Stating that "alarm bells should be ringing" the Labour politician cited government vaccines expert Professor Antony Harnden warning that "vaccines are almost certainly less effective at reducing transmission of this variant".
Mr Hancock accused the shadow health secretary of "a Captain Hindsight act", telling MPs: "He didn't seem to mention that we put India on the red list before this virus was deemed a variant, even under investigation, let alone a variant of concern.
"And indeed, we put India on the red list before other countries like Germany and Canada, stopped flying from India. We have a strong policy of restrictions at the border, and we will remain vigilant."
Cases of the new variant from India have nearly tripled to 1,313 in the past week in England.
But Mr Hancock said the UK had "increasing confidence" that Covid-19 vaccines currently in distribution protect against it.
It comes as more than 20 million people in the UK have now had more than two doses of the vaccine.
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