Covid: Which areas are being mass tested for variants?

Extra Covid tests are taking place in areas where new variants of coronavirus have been found.

This is known as surge testing and is used to prevent the spread of Covid outbreaks - especially new, more contagious variants, which might not respond as well to current vaccines.

Increased testing and enhanced contact tracing is carried out in very specific locations - local authority areas, postcodes or even individual streets.

Some of this testing is carried out by health officials going door-to-door.

Households in various of areas of Birmingham are being asked to take Covid-19 PCR tests after a small number of cases of the South Africa variant were found in the city. The cases are not thought to be connected to each other.

People aged over 16 in the Alum Rock, Glebe Farm and Tile Cross wards of Birmingham are the latest to be targeted.

Testing has already been introduced for people aged 16 and over who live or work in the Ladywood, Soho and Jewellery Quarter wards.

In addition, everybody aged 11 years and over who lives in, works in, or travels through the London boroughs of Lambeth and Wandsworth is being asked to take a PCR test.

Forty-four confirmed cases, and 30 probable cases, of the South Africa variant have been found in the area.

All identified cases are self-isolating, or have completed their isolation. Their contacts have been traced and asked to isolate.

Information on what to do is on the local authority websites:

People living in certain parts of SE16 in the London Borough of Southwark are also being contacted - after a case linked to the Lambeth/Wandsworth cluster was identified.

Surge testing linked to the South Africa variant is also taking place in parts of:

There are many thousands of different versions, or variants, of Covid circulating - including the Brazilian, South African and UK "variants of concern".

These strains of Covid-19 may be more contagious and dodge immunity to some extent.

An Indian variant is also being investigated by health officials in the UK.

The PCR (polymerase chain reaction) test

This involves swabbing your nose or throat, dropping the swab in a vial of liquid and sending it to a lab for analysis.

It is regarded as the most reliable test, but normally takes a day or longer to get a result.

People tested under the new variant surge programmes are being offered PCR tests.

The lateral flow test

This also involves a swab from the nose or throat, which is dropped into liquid. The solution is then added to a test strip which shows a result in 20-30 minutes.

Wherever you are in the UK, if you have symptoms you should book a free test online. You will be sent to a testing site or have a testing kit sent to your home.

If you have problems booking, call 119 in England, Wales and Northern Ireland or 0300 303 2713 in Scotland.

Anyone in England can now get two free lateral flow tests each week - even if they do not have symptoms. People in Scotland will also be able to apply for lateral flow tests from 26 April.

Anyone who gets a positive result test must immediately self-isolate for at least 10 days. NHS Test and Trace will tell their contacts to isolate if necessary.

Self-isolating means not leaving home for exercise or even to buy food, medicines or other essentials.

People in England who fail to self-isolate after a positive test can be fined up to £10,000.

Anyone on a low income who has been told to self-isolate can claim a £500 payment.

CORRECTION: A version of this story published on 1 March said that testing for variants was being carried out in the CM0 area around Southminster. It was in fact the CM13 area around Brentwood where additional testing was taking place.