Aside from your work environment itself (for which your employer should have taken steps to allow employees’ safe return to work), it’s understandable that you may have concerns about travelling to and from work on public transport. The UK Government guidance for avoidance of public transport if possible is of course easier said than done.
If you see this as causing a problem with your ability to return to work, then speak to your employer about other options. For example, your employer could consider:
It is of course the case that current Government advice will constantly change and your employer should be regularly checking this and following any amended guidance.