Business leaders are calling for a clearer picture of when coronavirus restrictions will be relaxed amid more worrying predictions on the UK economy.

But Prime Minister Boris Johnson has called for patience as he refused to give a timetable for the lockdown restrictions to be eased, warning acting too soon could lead to a second wave of cases and "economic disaster".

A survey of 1,000 of its members by the Institute of Directors revealed the growing demand for more information on the way forward.

Director general Jon Geldart said: "Over the last few days the clamour from our members for information on how, and when, coronavirus-related restrictions will begin to lift has increased substantially.

"Directors from all parts of the UK need to make plans for riding out the tempest, but they can't get very far if they have no idea what will be happening in a few weeks' time."

The institute's call comes as leading forecasting group EY Item Club said it would take three years for the UK economy to return to levels at the end of 2019.

Its latest report said GDP was set to collapse by 6.8 per cent this year before a slight upturn later in 2020 and a growth of 4.5 per cent next year - if lockdown controls start to be eased in May with further relaxations in June.

But the Prime Minister, speaking for the first time since his own recovery from the virus, said he could not risk acting too quickly.

He said: "I ask you to contain your impatience. I believe we are coming to the end of the first phase of this conflict and, in spite of all the suffering, we have so nearly succeeded.

"I know it is tough. I want to get the economy moving as fast as I can. But I refuse to throw away the sacrifice of the British people and risk a second peak.

"We simply cannot spell out now how fast or slow, or even when, these changes will be made."

He continued: "If this virus were a physical assailant, then this is the moment when we have begun together to wrestle it to the floor.

"And so it follows that this is the moment of opportunity, this is the moment when we can press home our advantage, it is also the moment of maximum risk.

"I know there will be many people looking at our apparent success and beginning to wonder whether now is the time to go easy on those social distancing measures.

He said the Government would make decisions with "maximum transparency".

The Prime Minister returned to work yesterday after more than three weeks off sick, including a spell in intensive care.