No, you do daily lateral flow tests instead. Some info here:
People "pulling a sickie" by telling falsehoods (e.g. claiming they haven't been double jabbed when they have) should not be tolerated. I think some are implying that this (a) will happen and (b) should happen, and it is gross misconduct and should result in dismissal.
I trust that the Unions will not be encouraging such practice; if it turns out they are, time for legislation to prevent their so doing.
And from 16th August, people who have been double jabbed will not be advised to isolate due to a contact (rather than an infection of themselves), rather they will be advised to take lateral flow tests.
I can't imagine many people choosing full self-isolation (remember, you are not allowed to leave your property at all for 10 full days - not even to go shopping for essentials, let alone to go to the pub) over taking a daily test and being able to resume life as normal. It is not just about staying off work, it is that you cannot go out - you are effectively under house arrest - the only exception is if the NHS or police instruct you to do so, or you would be in physical danger e.g. a house fire or domestic abuse.
Anyone who tells their employer that they are isolating but simply takes the time off work and carries on their social life as usual will be (a) breaking the law*, and (b) committing gross misconduct which would, quite rightly, render them liable for dismissal or at least strong disciplinary action - i.e. "pulling a sickie". And I hope anyone who does do that is sacked, because by doing so they would be bringing the railway and its majority of honest staff into disrepute, and if the Unions support them bang goes their credibility.
Clearly someone could self-isolate for the 10 days, but I really can't see many people choosing that option - being unable to go out at all for 10 days is pretty grim.
* Except if "pinged" on the phone app, which isn't legally mandatory, but carries advice based on the law for if T&T call you, so most employers will consider it the same.
Daily lateral flow tests is/was the scheme for 20 select employers.
From 16 August those pinged or advised to self isolate need to isolate other than attending a test centre for a PCR test, until they receive a negative result (and obviously the full isolation applies if it is a positive result).
This means anyone pinged is still typically going to need to isolate for 2 days while they get their test and await their result.
If you’re fully vaccinated or under 18, you will not need to self-isolate following close contact with someone who has COVID-19. You’ll still need to take a PCR test and self-isolate if it’s positive.