NHS trusts say they are rapidly increasing coronavirus testing on staff, but continue to be restricted by a shortage of equipment.

Some 2,000 frontline NHS workers have so far been tested for coronavirus, Downing Street has said, as it reiterated calls for trusts to use any spare testing capacity for staff.

But some NHS trusts say they are limited in the number of tests they can carry out due to continued shortages of swabs, reagents and testing kits.

One large district hospital in the midlands reported it was only able to test three staff members per day due to a lack of swabs, NHS Providers said.

Another trust in the West Midlands said while it could carry out up to 300 tests per day, a shortage of reagent and testing kit availability meant only 20 were carried out daily.

Despite there being capacity for 12,750 daily tests, only 8,630 were taken on Monday, the Prime Minister’s official spokesman told a Westminster briefing.

He said: “In terms of NHS frontline staff who have been tested overall, it’s now over 2,000 and staff will be getting the results fed back to them over the next few days.”

The spokesman said the Government was “very clear” that it wants more testing to be carried out.

“A clear instruction has been sent to all NHS hospital trusts that where there is capacity available it should be used on testing frontline staff and we would hope to see that happening,” he said.

NHS bosses have now been ordered to “max out” testing facilities so hospital staff are tested.

Around 1.2 million people work for NHS England in total.

In a letter to NHS trust chief executives on Wednesday, health officials said that labs should be “fully used” every day.

Spare tests can be given to hospital staff and those working in neighbouring ambulance and acute trusts, the letter adds.

When this has been implemented, and extra lab volumes become available, this will be rolled out to staff in GP services, social care, mental health and community services.

Northampton General Hospital NHS Trust set up a staff testing station over the weekend as part of a national pilot scheme, carrying out the first tests on Monday for those working in priority areas.

More than 1,000 workers have since been tested, with just 27 testing positive for coronavirus out of 184 results received so far.

The trust’s chief executive Dr Sonia Swart said: “Offering this testing means that we can give our staff the reassurance they need to be able to come back to work and know they are healthy.”

Prime Minister Boris Johnson said in a video posted on Twitter that increased testing would help “unlock the coronavirus puzzle”.

He said: “I want to say a special word about testing, because it is so important and as I have said for weeks and weeks, this is the way through.

“This how we will unlock the coronavirus puzzle. This is how we will defeat it in the end.”

Meanwhile, it has been reported that offers of help from some of the UK’s leading scientific institutions to boost Britain’s rate of coronavirus testing have been ignored by medical officials.

The Daily Telegraph says officials have repeatedly ignored offers from entities including Oxford University and the renowned Francis Crick Institute involving hundreds of testing machines and trained personnel.

While other nations including Germany, South Korea and Australia have already tested hundreds of thousands of their citizens, Britain has been lagging behind.

The number of daily tests fell on Tuesday to 8,240, for a total of 143,186 tests since the end of February, according to Government figures.

Professor Matthew Freeman, head of Oxford’s Dunn School of Pathology, one of Britain’s leading disease research centres, told the paper his repeated offers to provide dozens of specialised machines and expert staff had been largely ignored by Public Health England (PHE).

He said his department had 119 of the crucial PCR machines, or thermal cyclers, used to identify tell-tale genetic signs of coronavirus, but health officials had accepted only one.

PHE offered a defence of its response to the outbreak, with a spokesman telling the paper it had rapidly developed, validated and delivered an accurate test, which had spread to 12 different sites in England, and that this represented “the fastest deployment of a novel test to PHE and NHS labs in recent history, including in the swine flu pandemic”.

Meanwhile, Chris Hopson, chief executive of NHS Providers, said everyone including the Government, central NHS leaders, procurement chain, trusts and their pathology labs are all “working very hard to expand coronavirus testing capacity as fast as possible”.

He said: “Early results from a very small sample suggest that there is a significant potential prize here in terms of the number of staff who could return to work.

“But it is striking how many trusts are also reporting significant constraints due to swab and reagent shortages.

“Trust leaders will do the very best they can with the resources they have available.

“But these shortages, which trusts do not control, need to be overcome if we are to see the growth in testing capacity we are all looking for.”