Extra trains are expected to take thousands more people back to work under the Government’s plan to accelerate economic activity by lifting lockdown restrictions.

After the first weekend in which people in England could enjoy sunbathing and picnics outdoors, public transport operators were preparing to carry many more commuters to building sites, factories and offices on Monday.

The move comes at the start of the first full working week since Boris Johnson set out his plan for easing the coronavirus lockdown in England, urging those employees unable to work from home to return to their places of employment.

He has faced criticism from some unions and opposition MPs who accused him of moving too quickly while the devolved administrations in Scotland, Wales and Northern Ireland have refused to follow suit.

Recycling centres in England will reopen after a reported increase in fly-tipping, discount chain Poundland will reopen 36 stores, and early-morning swimmers can enter the water at Britain’s oldest swimming club at the Serpentine in Hyde Park, west London.

And The Times newspaper reported lorry drivers will make up the bulk of exemptions to plans to impose a 14-day quarantine on international travellers regardless of mode of travel.

The paper said hauliers will account for around two-thirds of those who will not be asked to self-isolate in what it called a “blow to the airline and tourism industries”. Further exemptions are to be agreed at a Cabinet meeting, the Times added.

It comes after the Government announced a ground-breaking deal which could make millions of vaccine doses available in the UK as early as September.

A further £84 million has been invested in teams from Oxford University and Imperial College London as they carry out clinical trials in a bid to find a vaccine that could finally end the pandemic.

Oxford has signed a global licensing agreement with pharmaceutical giant AstraZeneca which could see it supply 100 million doses of a vaccine – with 30 million going to the UK – if the current human trials prove successful, Business Secretary Alok Sharma said on Sunday at the Downing Street news conference.

Despite the announcement, the Prime Minister earlier warned there was still a lot to do and the search may never be successful.

The latest Department of Health figures showed 34,636 people had died in hospitals, care homes and the wider community after testing positive for coronavirus in the UK as of 5pm on Saturday, up by 170 from the day before.

Ministers at Westminster are keen to move to the next step of loosening the lockdown which would see primary schools in England begin a phased reopening from June 1.

Cabinet Office Minister Michael Gove said measures were being put in place to ensure the safety of children and teachers, although he acknowledged there was no guarantee it would not lead to a rise in the number of Covid-19 cases.

He urged councils such as Liverpool and Hartlepool – which have said they will not be opening schools in June – to reconsider their opposition to the plan.

But Policing Minister Kit Malthouse suggested schools may not be allowed to return on June 1, telling BBC Radio 4’s Westminster Hour programme: “The Prime Minister said when he announced (the date) that it’s conditional on the numbers going in the right direction.”

The lack of certainty comes as the chief executives of 22 academy trusts responsible for some 350,000 children warned schools must reopen soon to avoid “irreparable” and “calamitous” damage to disadvantaged pupils.

Signatories including Dixons Academies Trust’s Sir Nick Weller and Dame Rachel de Souza of Inspiration Trust said in a letter: “If we do not take action and reopen schools soon, the impact of lost learning could be irreparable. The gaps between the ‘haves’ and the ‘have nots’ in our communities are widening daily and we will face years of frantic endeavour, in inevitable austerity, to compensate for this dislocation of learning.”

If we do not take action and reopen schools soon, the impact of lost learning could be irreparable

Chief executives of 22 academy trusts

However, a number of teaching unions remain sceptical and are seeking further talks with Education Secretary Gavin Williamson in order to secure further reassurances about the Government’s proposals.

From Monday, train companies are increasing services to 70% of standard timetable capacity to reflect the loosening of travel restrictions, said industry body the Rail Delivery Group.

But to enable social distancing, their capacity will be reduced to as little as 10% of normal levels, and passengers are being urged to avoid non-essential travel.

Unions have stepped up calls for safety measures in workplaces and have told their workers they will be supported if they refuse to work on safety grounds.

Officials have complained the Government is sending millions of workers mixed messages by telling them to return to work but avoid public transport even as more services are laid on.