Prime Minister Boris Johnson has urged revellers to take a coronavirus test ahead of New Year’s Eve celebrations but many people cannot access one amid supply issues.

Mr Johnson encouraged punters to enjoy the night in a “cautious and sensible way” by ordering a test and booking a booster jab – but pharmacies have warned of “huge” problems with lateral flow deliveries and PCRs are not available to order online for most of the UK.

While visiting a vaccination clinic in Milton Keynes on Wednesday, Mr Johnson told reporters: “I think 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.”

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

Speaking on BBC Radio 4’s Today programme, Ms Hannbeck said: “What our members are telling us is that demand for the lateral flow tests is very high at the moment due to the current guidelines around self-isolation.

“Pharmacies are reporting that every five minutes, approximately, somebody comes in to the pharmacy asking for a test.

“But, unfortunately, because of the issues around supply being patchy and inconsistent, it means that those who come for the test don’t always get it, which is very stressful not just for the pharmacy team but for the patient.

“The scale of the problem is huge because the demand is high, because of the current guidelines.”

Nearly 900,000 test kits are being provided per day according to the UK Health Security Agency – which is double the supply seen before December 18 – but Ms Hannbeck said this “isn’t enough to meet the demand” and deliveries have been “patchy”.

In a repeat of events in the weeks before Christmas, the Government website is reporting that there are no PCR tests available for people including key workers in England and Northern Ireland.

There are also “very few available” in Scotland, while people in Wales can order the tests online for now.

Shadow health secretary, Wes Streeting, described the dearth of supplies as a “total shambles” caused by “the Conservative Government’s incompetence”.

The Labour MP 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.”

The UKHSA has said tests may be temporarily unavailable on the Government website at points throughout the day due to “exceptionally high demand” and urged people not to order more tests before using the ones they have.

A spokesman said: “During periods of exceptional demand there may be temporary pauses in ordering or receiving tests, to ensure we manage distribution across the system and support changing requirements for LFD and PCR tests.

“Reduced postal schedules also impact on delivery capacity over the Christmas period.

“Rapid tests are available to order directly to people’s homes via gov.uk and availability is refreshed regularly throughout the day.

“We encourage people to re-visit the site every few hours if they are unable to order tests as more will become available – and to please ensure they are making use of any tests they already have at home before ordering or collecting more.”