The programme comes as Prime Minister Andy Burnham has pledged to end rough sleeping in the UK.

Burnham, said: ‘Nobody should have to sleep rough, but while people are on the streets, we have a duty to keep them safe.

‘This NHS initiative will provide vital vaccinations, protecting some of the most vulnerable people from potentially deadly infections.

‘We are delivering for people in crisis now, while changing the system for the long term so everyone has a route off the streets for good.'

NHS teams and partners hope increasing vaccination among vulnerable groups can also help to protect the wider public by reducing the spread of flu through communities, helping prevent avoidable hospitalisations and easing winter pressures on NHS and emergency services during periods of high demand.

The NHS roll out comes after the Government accepted expert advice from the Joint Committee on Vaccination and Immunisation (JCVI) to offer pneumococcal and seasonal flu vaccinations to the homeless. In addition, for the first time this year, some pharmacies can now vaccinate children aged between two and under 18 who are in clinical risk groups.

Other groups eligible from this week include people aged 65 years and over, all adults in clinical risk groups from 18 to under 65, residents of long-stay residential care homes, carers in receipt of carer's allowance, people who are the main carer of an elderly or disabled person, and close contacts of people who are immunocompromised. Eligible frontline health and social care professionals are also now encouraged to come forward for their flu jabs.

Pregnant women, school-age children and two- and three-year-olds have been offered flu vaccinations since 1 September in line with JCVI guidance.