British Prime Minister Boris Johnson will plot a path out of COVID-19 lockdown on Monday in an effort to gradually reopen the battered $3 trillion economy, aided by one of the fastest vaccine rollouts in the world.

With more than 120,000 fatalities, Britain has suffered the world’s fifth-highest official death toll from the pandemic and its biggest economic crash in more than 300 years.

But a fast start to the vaccine rollout plus a near-two month tough national lockdown means Johnson can now set out a phased easing of the restrictions, prioritising a return to schools and social mixing outdoors.

“Our decisions will be made on the latest data at every step, and we will be cautious about this approach so that we do not undo the progress we have achieved so far,” he will say, according to his office.

Under pressure both from politicians in his own Conservative Party to restart the economy, and from scientific advisers who fear a resurgence of the virus if he unlocks too quickly, Johnson has a difficult course to chart.

He has appeared much more cautious in recent months and his health minister Matt Hancock said on Sunday any easing, such as the reopening of schools on March 8, would be followed by a couple of weeks to detect the impact on the wider population.

Johnson will set out four tests to be considered before each new relaxation is taken, including the speed and success of the inoculation programme, the state of infection rates and the impact of any new variants of the virus.

Britain moved faster than much of the West to secure vaccine supplies and has been inoculating people rapidly since December, a strategy that has driven sterling and stock markets higher on hopes of an economic rebound.