(Corrects length of quarantine to 10 days from 14 in firstparagraph)

LONDON, Feb 15 (Reuters) - Passengers arriving in Englandfrom Monday from any of 33 "red list" countries will have tospend 10 days quarantined in a hotel room under new borderrestrictions designed to stop new variants of the coronavirus.

The launch of the system, which had already been set outearlier this month, marks the government's latest effort toprevent another relapse into crisis after a second wave of amore contagious COVID-19 variant forced the country into aprolonged lockdown at the start of the year.

New cases, deaths and hospitalisations are falling sharplyand the rollout of vaccines has reached more than 15 millionpeople, but ministers are still wary that new mutations fromoverseas might unravel that progress.

"As this deadly virus evolves, so must our defences," healthminister Matt Hancock said in a statement. "The rules cominginto force today will bolster the quarantine system and provideanother layer of security against new variants at the border."

The government has lined up 4,963 hotel rooms that must bebooked in advance as part of a 'quarantine package'. Thesehotels will have a "visible security presence", the governmentsaid. A further 58,000 rooms are on standby.

Countries on the red list include South Africa and Brazil -both of which have seen variants of the virus that could reducethe efficacy of existing vaccines.

Ministers have been criticised by opponents for being tooslow to close the door to new variants, having first announcedplans for hotel quarantine in January.

Arrivals from countries not on the red list are required toquarantine at home for 10 days and take two COVID-19 tests.

The tougher quarantine restrictions also carry heavy finesand penalties with potential prison sentences of up to 10 years.(Reporting by William James; editing by EmeliaSithole-Matarise)