New coronavirus rules have been put in place in England from today in a bid to halt the spread of Covid-19.
Under the new rules, repeat offences - and the most serious breaches - could be punished with fines of up to £10,000.
The crackdown is part of a bid to reduce the recent rising cases of Covid-19, with the Prime Minister warning the UK is facing a "second wave".
So what are the new Covid rules and how does it all work?
If you test positive for coronavirus it will be a legal requirement to self-isolate or when told to by NHS Test and Trace in England.
Test and Trace call handlers will make regular contact with those self-isolating to check they are doing so.
What are the new coronavirus measures?
What happens if you don't adhere to the rules?
If someone is thought to be breaking the law, call handlers will be able to escalate the case and raise it with Local Authorities or the police.
Boris Johnson said the shift to "legal obligation" was important in the "fight" against coronavirus.
If you do not stick to the rules you could face fines starting from £1,000 if you break the rules. This could rise up to £10,000 for repeat offenders.
Those who are on low-income and are made to self-isolate and unable to work from home will be entitled to a £500 payment to cover their loss of earnings.
What is happening in Wales and Scotland?
Coronavirus laws are being tightened further in Neath Port Talbot, the Vale of Glamorgan and Torfaen in response to a growing spread of cases, First Minister Mark Drakeford has confirmed.
Local restrictions will come into force from 6pm on Monday, 28 September - and means the majority of South Wales is now in lockdown.
People will not be allowed to enter or leave these areas without a reasonable excuse
People will only be able to meet people they don’t live with outdoors for the time being
Extended households rule will come to an end
Local restrictions are already in place in seven other areas of South Wales – Blaenau Gwent, Bridgend, Caerphilly borough, Llanelli in Carmarthenshire, Merthyr Tydfil borough, Rhondda Cynon Taf and Newport.
Restrictions also come into force in Cardiff and Swansea at 6pm tonight.
Elsewhere in Scotland, students have been told they can return home from university accommodation on a long-term basis, as long as they follow rules on self-isolating.
It comes as more than 600 people are self-isolating at the University of Glasgow after 124 students tested positive for coronavirus.
Higher Education Minister Richard Lochhead said: "We would encourage students to remain living in their current accommodation where they are able to, so they can continue to benefit from both a blend of digital and in-person learning, where that is possible and the opportunity to engage with others, within the restrictions, to build new networks and to make new friends."
"However, we know that many students may be struggling with the prospect of not being able to return home to visit family and other support networks, especially if is the first time in their life they have been away from home."