Virus specialists are critical of government plans to try to keep virus out of UK by monitoring ports and airports

The first Ebola cases will soon emerge in the UK according to the government’s chief medical officer, who said the country should expect “a handful” of people to fall ill with the disease in coming months.

Dame Sally Davies issued her warning on Saturday following a national exercise to test Britain’s readiness for an Ebola outbreak amid growing criticism that government priorities for dealing with the threat are seriously misplaced.

Davies said: “It will not be surprising if we have spillover into this country so I would expect a handful of cases in the next few months. This vitally important exercise gave a very realistic test of how prepared the system is to deal with a case of Ebola. Today has included a variety of scenarios involving personnel from hospitals, ambulance services and local authorities around the country.”

Despite the predicted spread, Dr David Nabarro, the UN’s senior system coordinator for Ebola, told the BBC’s Up All Night on Sunday morning that he believed the disease would be “under control” in three months.

While the health secretary, Jeremy Hunt, announced – after chairing a simulated meeting of the emergency Cobra committee as part of the UK’s test – that the exercise had been reassuring and “extremely useful”, other politicians and scientists described government plans as futile. The eight-hour exercise involved actors simulating symptoms of Ebola with one person “collapsing” in a Gateshead shopping centre and being placed in isolation at the Royal Victoria Infirmary in Newcastle upon Tyne, and was held as a preamble to the introduction of screening for the virus at large airports and terminals. But many experts have voiced serious misgivings about the introduction of screening, ordered by David Cameron as part of the UK’s contingency plan against Ebola, which has killed more than 4,000 people in west Africa.

Professor David Mabey, of the London School of Hygiene and Tropical Medicine, said screening would be futile. “There won’t be anyone coming from these [west African] countries because all direct flights have been cancelled,” he said. “Are they going to screen everyone from Brussels, Paris, Frankfurt and Amsterdam? That would lead to a lot of delays and disruption.”

This point was supported by virologist Dr Ben Neuman of Reading University, who said there was no “strong scientific case that airport screening will help keep Ebola out of the UK”. Professor Tom Solomon, Liverpool University’s head of infection and global health, said evidence “suggests such measures won’t make a large difference”.

An even more trenchant criticism of the government’s emphasis on spotting Ebola victims as they entered Britain was provided from Sierra Leone by Andrew Gleadle, programme director for the International Medical Corps. “I’d like to see is a little less hysteria in the US and the UK,” he said. “We may get a few isolated cases [in the west] but we’re not going to get an epidemic. We need more focus on west Africa, where the real problem is.”

Children’s charity Plan UK, said the only “truly effective” way of preventing Ebola reaching Britain was to tackle the crisis in west Africa. “As the government introduces more measures to try to prevent the arrival of Ebola in this country, it would be fatal to forget that the best way to help the UK is to help west Africa,” said chief executive Tanya Barron. “This is an outbreak that needs tackling at source, and to change the course of the crisis, we mustn’t simply hunker down in developed nations. We must break the chain of infection.”

Others raised doubts about the arrangements for screening at Heathrow and Gatwick airports and Eurostar rail terminals. A spokesman for Gatwick said the airport had not received any instructions on how screening should be carried out. Labour MP Keith Vaz said a lack of precise information available about the screening was “shambolic”.

The US has begun screening travellers from the three west African countries most affected by Ebola infections – Liberia, Sierra Leone and Guinea – at JFK airport in New York and was expecting to expand this to Newark Liberty, Washington Dulles, Chicago O’Hare and Hartsfield-Jackson in Atlanta later this week.

It was also confirmed that more than 750 UK military personnel and the medical ship RFA Argus were being sent to west Africa to help in the efforts to contain the Ebola outbreak.

“What we are focusing on as a country is taking action right across the board to deal with this problem at source,” the prime minister said on Saturday. “What we do is listen to the medical advice and we act on that advice, and that’s why we are introducing the screening processes at the appropriate ports and airports.”

Meanwhile, doctors in Macedonia have ruled out the Ebola virus as the cause of death of a British man in the Balkan country on Thursday. “We have just received the results from the lab in Hamburg and they are negative for Ebola, which means that the patient did not have the Ebola virus,” said Dr Jovanka Kostovska of the Macedonian health ministry’s commission for infectious diseases.