Boris Johnson’s Government is scrambling to secure supplies of Covid-19 tests as the Prime Minister urged people to get swabbed before enjoying New Year celebrations.

Ministers acknowledged a worldwide supply issue is hitting the UK as people again struggled to get tests through pharmacies or delivered to their home.

Health Secretary Sajid Javid set out the issues in a call with a Tory MP, acknowledging there is not a quick fix to a problem caused by global demand.

Leyla Hannbeck, chief executive of the Association of Independent Multiple Pharmacies, has said patients are often unable to find Covid-19 tests in chemists because of “patchy” and “inconsistent” supplies.

The Government website showed no PCR tests were available for home delivery – even for essential workers – in England or Northern Ireland, with “very few” in Scotland, while Wales had availability only in some regions.

Home delivery slots for lateral flow tests were also unavailable on Wednesday afternoon.

Officials acknowledged that during periods of exceptional demand there could be “temporary pauses” in ordering or receiving tests in an attempt to manage distribution across the system.

The reduced postal system over Christmas has also added to the issues.

In Scotland, First Minister Nicola Sturgeon said testing will be prioritised for essential workers as sampling processing capacity is “under pressure”.

She told the Scottish Parliament that “there were steps taken to constrain demand in England last night (Tuesday)”, meaning no slots were available to book at physical test sites but “an administrative error” also restricted appointments at sites in Scotland, Wales and Northern Ireland.

The UK Health Security Agency (UKHSA) is understood to temporarily pause the booking portal to limit the flow of tests into laboratories when there is “exceptionally high demand”.

Tory MP Sir Roger Gale told the PA news agency that Mr Javid had admitted there is a problem with supplies – previously ministers and officials had insisted they had sufficient stocks but the problems were in delivering them to people’s homes or pharmacies.

The North Thanet MP said: “Saj was very honest with me, he said, ‘look, there isn’t a quick fix’.”

The Government has encouraged regular testing as a way of keeping England’s economy open while the devolved administrations have closed nightclubs and taken other steps to limit social contact.

Tests are also being used to replace self-isolation for contacts of confirmed Covid-19 cases, while people returning to work following the Christmas break has also added to demand.

Sir Roger said “we have created the demand in England which we now can’t satisfy” as a result.

He added: “The Prime Minister has now found himself caught between the Covid Recovery Group and supporters and the scientists.

“We are now facing the situation where No 10 is saying ‘go and get tested’ and the Department of Health is saying ‘we haven’t got the tests, we can’t do it’.”

He said Mr Javid is “busting a gut” to get supplies “but we’re competing with a global market”.

During a visit to a vaccination centre in Milton Keynes on Wednesday, Mr Johnson urged people to get tested before New Year’s Eve festivities.

He told reporters: “Everybody should enjoy New Year but in a cautious and sensible way – take a test, ventilation, think about others but, above all, get a booster.”

Shadow health secretary Wes Streeting said: “The failure to make enough tests available weeks after they became a requirement is a total shambles.

“People are trying to do the right thing, follow the Government’s own advice, and test themselves regularly, but are prevented by the Conservative Government’s incompetence.

“They need to get a grip and provide enough tests so people can keep themselves and everyone else safe.”

Ms Sturgeon said: “The current surge in cases means testing capacity – sampling and processing – is under pressure.

“So we are now prioritising some slots for essential workers – such as NHS and transport staff – as well as for those who are clinically vulnerable or eligible for new Covid treatments.”

It comes as a further 183,037 lab-confirmed Covid-19 cases were recorded in the UK as of 9am on Wednesday, the Government said, another new record for daily reported cases. The total includes reported figures for Northern Ireland covering a five-day period.

The Government said a further 57 people had died within 28 days of testing positive for Covid-19.

Separate figures published by the Office for National Statistics show there have been 173,000 deaths registered in the UK where Covid-19 was mentioned on the death certificate.

A UKHSA spokesman said: “We are delivering record numbers of lateral flow tests to pharmacies across the country, with almost eight million test kits being made available to pharmacies between today and New Year’s Eve.

“We have made 100,000 more PCR booking slots available per day since mid-December and we are continuing to rapidly expand capacity – with over half a million tests carried out on 23 December alone and delivery capacity doubled to 900,000 PCR and LFD test kits a day.

“If you have not been able to get the test you need from gov.uk, please keep checking every few hours as more PCR and LFD tests become available every day.”

Meanwhile, Mr Johnson continued to drive forward the Covid-19 vaccination programme, saying he “cannot stress too much” how important a booster shot is.

Mr Johnson said 2.4 million eligible double-jabbed people are yet to take up the offer of a booster, adding: “I’m sorry to say this but the overwhelming majority of people who are currently ending up in intensive care in our hospitals are people who are not boosted.

“I’ve talked to doctors who say the numbers are running up to 90% of people in intensive care who are not boosted.”

There are no official NHS figures on the vaccination status of people in intensive care but medics have warned the vast majority are either unvaccinated or have not had all their doses.