What does a faint red line on a lateral flow Covid test mean?

People testing for coronavirus using rapid lateral flow test kits have reported seeing a faint red line in their result — but what does it mean?

Demand for the home testing kits has surged in recent weeks, with people eager to check if they have Covid before attending any Christmas or New Year's celebrations.

If no red line appears next to the 'T' symbol on the test result, it means the person does likely not have the virus at that time.

But a number of people have expressed confusion as the line may appear faint, rather than a solid red.

According to the government's official guide for self-testing, even the faintest line can suggest the person has Covid.

The guide says: "Two lines, one next to C and one next to T, even faint lines, shows the test is positive. The positive line may be weak. You should hold the test strip up to the light and examine closely to feel confident of the result.

"If you get a positive result, it means you are currently likely infected with coronavirus and risk infecting others."

If no lines or one line next to the 'T' appear, the test is void.

As lateral flow tests are not 100% accurate, people who test positive with them are advised by the government to book a spot at a PCR testing centre.