"The opening up of the economy following the COVID-19 outbreak is being supported by NHS Test and Trace. You should assist this service by keeping a temporary record of your customers and visitors for 21 days, in a way that is manageable for your business, and assist NHS Test and Trace with requests for that data if needed. This could help contain clusters or outbreaks. Many businesses that take bookings already have systems for recording their customers and visitors – including restaurants, hotels, and hair salons. If you do not already do this, you should do so to help fight the virus. We will work with industry and relevant bodies to design this system in line with data protection legislation, and set out details shortly."
https://www.gov.uk/guidance/working-safely-during-coronavirus-covid-19/restaurants-offering-takeaway-or-delivery