London: The Delta variant of COVID-19, or the B1.617.2 variant first identified in India, is around 40 per cent "more transmissible" than the Alpha or so-called Kent variant of concern, making the unlocking plans set for June 21 "more difficult", UK Health Secretary Matt Hancock said on Sunday.The senior Cabinet minister the government was "absolutely open" to delaying the final lifting of England's Covid lockdown on June 21 if necessary.Hancock insisted June 21 was a "not before" date to end restrictions and 10 Downing Street "would look at the data".He said the spread of the Delta variant was behind a recent rise in coronavirus infections in the country.However, he pointed out that a majority of those in hospital as a result of the Delta.