Sick notes can now be written by more health professionals thanks to new rules aimed at reducing workload for NHS GPs.
Nurses, pharmacists, physiotherapists and occupational therapists can legally sign people off work from today. Until now only GPs had the power to authorise absence from work.
Sick notes are needed to prove to employers why a person should be allowed off work for more than seven days.
The relaxation of the rule could also make it easier for people to claim Universal Credit and certain benefits aimed at supporting those who are unable to work because of long-term illness.
It has been introduced to relieve pressure on doctors who have become overwhelmed by record-long waiting lists in the wake of the pandemic.
Data from April shows that 6.48 million people are awaiting NHS treatment, including more than 300,000 who have been waiting over 12 months.
The change has taken effect in England, Scotland and Wales and is being mirrored in Northern Ireland.
Health Secretary Sajid Javid said: “Slashing unnecessary bureaucracy is key to ensuring more patients can see their GP quickly and get the care they need as we bust the Covid backlogs."
He wants to cut bureaucracy faced by doctors so they can deliver an additional 50 million appointments a year by 2024.
The Government is relaxing the rules further after changing them in April so that GPs had the option to sign sick notes digitally instead of having to use a pen and paper.
Mr Javid has pledged to oversee a "digital revolution" to accelerate NHS access.
A host of new features are set to added to the NHS app like the ability to directly chat with a GP, manage hospital appointments and access records.