"In cash terms, we have the highest government debt we have ever had. But the cost is exceptionally low, and even if we increase what is described as borrowing as a consequence of coronavirus the impact will still be very small given current, exceptionally low interest rates, which look like they will persist for a very long time.

Please do always recall, that every penny the government spends on interest becomes someone's income - and most of it in the UK. And there is good reason for that: UK national debt is just a savings mechanism. There is nothing more menacing or threatening about it to our wellbeing than the amount saved in banks and building societies."
https://www.taxresearch.org.uk