People told to self-isolate by the NHS Covid-19 app are not eligible for the £500 support payment because its notifications are "advisory", the Government has confirmed, prompting a warning that the app is "not fit for purpose".
The Department for Health and Social Care (DHSC) said people would only get the payments if told to self-isolate by human contact tracers, whose instructions are mandatory. People face fines of up to £10,000 if they fail to comply.
Professor Paul Hunter, an expert in health protection at the University of East Anglia who has advised the World Health Organisation, said the disparity could cause potentially infectious people not to isolate, further "undermining" the Test and Trace system.
The rules have also been causing confusion, with some people spending days trying to claim their £500 after receiving an app alert only to be given contradictory advice on whether they were eligible. One couple who self-isolated after an app alert told The Telegraph they felt they were being "punished" for following guidelines after learning they were ineligible for support.
The news comes after Boris Johnson, the Prime Minister, admitted on Thursday that he was "frustrated" and wanted Test and Trace to improve after figures showed it had reached the lowest numbers of close contacts of infected people yet.
The app, which has been downloaded more than 18 million times since September, is the newest part of the system and uses the Bluetooth signals on smartphones to log when users come into close contact. It sends an alert to users to self-isolate when one of their close contacts tests positive.
Meanwhile, there are concerns in the Government that the Test and Trace system is becoming less effective at containing the virus, with only around 20 percent of people are estimated to be strictly following self-isolating instructions.
Last month, ministers unveiled a £500 support package for people on low incomes who are told to isolate in an attempt to bolster compliance. But on Friday, the DHSC confirmed the money was only available to those contacted by human contact tracers
A spokesman said: "If you are on a low income and you are asked by NHS Test and Trace to self-isolate, either due to a positive test or as a close contact of a case, you may be entitled to a payment of £500 from your local authority, regardless of whether you booked your test through the app.
"The NHS Covid-19 app is voluntary, with users of it remaining anonymous, which means that currently people are not eligible for the support payment if they are advised by the app to self-isolate, but we are actively exploring ways to expand the payment scheme to include this group of users."
Prof Hunter urged the Government to extend the support to app notifications to ensure people who could be infectious did not go out and spread Covid.
He said: "If the app is there to try and get people to self-isolate who may be infectious, and as far as I can tell that is the sole purpose of the app, if people are not able to do that because they can't afford to then the app is not fit for purpose."
The uncertainty over who is eligible for support payments has already seen people self-isolate under the mistaken impression that they could claim for income they lost.
Dario Brizzi, 25, from Swindon, said he and his partner Megan, a hairdresser, ended up having to use their savings to pay their bills after she received an app notification telling her to self-isolate last Tuesday. The couple spent four days trying to claim the £500 from their local council for income she lost before being told they were not eligible and then also being wrongly told that it was mandatory for her to continue to isolate.
Mr Brizzi, who works for a housing association and is able to work from home, said he felt the couple had been "punished" for trying to follow the rules.
He told The Telegraph: "As the Government, you can't say: 'Download, it will keep you safe and keep others safe' as when people know about this they won't download the app. I told her to delete the app and I will never download the app."