The government has been urged to improve the coordination of food deliveries to vulnerable people across the UK amid warnings that thousands are being underserved during lockdown.

Consumer and disability rights groups have raised concerns that a number of elderly or disabled people, or those who have an existing illness that puts them at greater risk of contracting coronavirus, were still struggling to purchase groceries.

The government has shared its list of more than 400,000 vulnerable shoppers with supermarket chains including Tesco and Sainsbury’s.

The former has contacted people on that list and has already made deliveries to 300,000 of them as part of broader efforts to ramp up its online capacity.

Britain’s biggest grocer is now able to deliver 1.2 million grocery orders every week – double the number it could fulfil prior to the pandemic.

Sainsbury’s is prioritising 800,000 elderly and vulnerable shoppers, while around a third of Waitrose’s 120,000 delivery slots last week were taken up by those classed as vulnerable.

Despite such efforts from grocery retailers, consumer group Which? said it has been contacted by more than 1,000 vulnerable, elderly or disabled people who were having difficulties getting home deliveries.

It called on the government to implement “stronger coordination” to ensure all customers were being served during lockdown.

Which? head of consumer protection Sue Davies said: “Based on the huge number of reports we’re seeing from vulnerable people struggling to get access to basic food and supplies, it’s clear that the current system is not working for those who need it the most.

“Without easily accessible and clearer information for these people, and stronger coordination between the UK’s central and devolved governments, the food industry, local authorities and local charities, there is a risk that many will go hungry during this pandemic.”

Disability charity Scope’s executive director of strategy James Taylor said some disabled customers “have been forced to risk their health” by visiting supermarkets because they could not get home-delivery slots.

Almost half of the 600 disabled adults Scope surveyed said they had issues purchasing essential items. More than a third said they had been unsuccessful in trying to book an online delivery slot during the past three weeks.

The government has identified around 1.5 million people as being particularly vulnerable during the health emergency.

It has set up a food parcel delivery scheme to support that group and has delivered more than 900,000 of those in the past five weeks.