Who The Government Borrows From

We hear a lot Government borrowing and how the Government are looking to borrow £62bn this year but i have never understood who exactly we borrow it from.
Someone, somewhere must be lending out all this money because where else are we getting it from but it isn't the World's other richest countries as they are all in massive debt themselves so who are we trying to tap up to lend us £62bn?
The answer is no-one as the government borrows from financial institutions, like pension funds, investment funds, banks, insurance companies and also private savers by selling bonds, or gilts, which is a IOU to guarantee that you will pay them back later at an agreed date which could run from anywhere to a year or the next 55 years.
Makes sense but then my next question is how can the UK be the 5th richest nation in the World when it needs to borrow £62bn to run it and the latest ONS figures show we have a national debt of £1,798.5bn?
Economics, go figure.