Tougher restrictions are now in place in Brentford and the rest of London as part of the introduction of the new Tier 4.

The restrictions have been introduced following a rapid rise in Covid-19 infections attributed to the spread of a new variant of the virus.

There is no current evidence to suggest the new variant causes a higher mortality rate, that it affects vaccines and treatments, or that testing will not detect cases.

However, given the increased infection rate of the new variant, the government ruled that the Christmas bubble policy will no longer apply in Tier 4 areas.

How long will Tier 4 last?

The tiers will be reviewed on 30 December, as part of a wider review of restrictions.

However, speaking on Sunday morning, Health Secretary Matt Hancock hinted that the tight new restrictions could remain in place until a vaccine reaches a large part of the population.

Speaking on Sky News, he said: "We can see the way through this but it is going to be a difficult few months."

But what does Tier 4 mean?

Under Tier 4 restrictions, non-essential shops, hairdressers and leisure and entertainment venues will close, with a new 'stay at home' message introduced.

People who need to travel for education or childcare will be exempt, and exercise will be unlimited. Where people cannot work from home, they are still able to travel to work.

I am in Tier 4. What does that mean for travel?

Unless there is an essential reason for you to travel – for work, education, medical treatment, caring responsibilities and urgent compassionate reasons such as to visit someone who is terminally ill – you will be expected to stay at home.

What's allowed during the festive season under tough new measures?

Under the measures, households will not be allowed to mix, but one person will be allowed to meet with one other person outside in a public space.

Support bubbles and those meeting for childcare will be exempt.

Those who are clinically vulnerable should not go to work while limiting time outside away from their home.

Tier 4 residents must not stay overnight away from home, and cannot travel abroad.

People in all tiers are advised to stay local, and 'think carefully' about whether they need to travel abroad.

What can people do over Christmas?

Students are considered to be part of the household to which they have returned for Christmas and are not treated as part of their term-time household for this period

Children under 18 whose parents do not live together may be part of both parents' Christmas bubbles, if their parents choose to form separate bubbles

Christmas Day

Initially, the plan across the UK was for up to three households to be allowed to form one Christmas bubble.

However, following a rise in infection rates since the announcement of the Christmas plans, those rules have now changed.

The three household rule still applies in most of England - only those in Tier 4 will not be allowed to mix at all on Christmas Day.