Slowly and bit by bit. It will be years worth of crap to deal with it. But it all falls off 6 years after it was on, so if it's defaults that are on there that you have no chance of repaying, then you might be better off hanging on.
Have you printed off the full report, not just the credit score? If you've already had your free trial then you can apply for a £2 statutory report, it doesn't have to be a £15 a month job.
If you have printed the report off, what are the highlights?
I was bankrupt which was discharged in 2017. Obviously left me with terrible credit. I got a very high interest credit card, paid it on time every month and it built up my credit so that I was able to get a very low rate credit card with excellent benefits (no interest on balance transfers for 2 years and purchases for 1 year). check all of the credit reference agencies as they will all rate you differently, correct any misinformation and never miss any payments or go overdrawn. It takes time
My score was 50 x4 years ago! I was in 12k of debt and just littered with defaults and had two CCJ’s. I cut up all credit cards and cancelled all credit accounts and overdraft etc.
To sort the debt first thing I did was make a list of all the debts smallest to largest and a separate list for priority debt (council tax etc) then I phoned up all my creditors explained the situation and they agreed to freeze all interest and charges if I made a ‘token payment’ of £1 a month, once all those were set up I then chucked money at the debts one by one so I paid them off in full from smallest to largest, any that were really big l split into x3 (or whatever works for you) monthly payments.
The CCJ’s I tackled separate and alongside by setting up a direct debit with them to be paid monthly. I did this for council tax too, it was sometimes hard to keep on top of but I made lists and spreadsheets and kept track of everything.
I also learnt how to budget properly and save for an emergency fund etc, it took two years for my debt to be paid off and as each account was satisfied my credit score got slowly better and satisfied accounts are better than defaulted ones, and as the years go by they are slowly dropping off my report and my score jumps up a fair amount when that happens.
It’s currently hovering around 500ish on clearscore and Equifax, the last of the satisfied accounts will fall off my report nest February and then I’ll give it a few months for my score to improve even more and then I’ll apply for a credit builder credit card and build from there.
Just make sure to pay all your bills on time from today, and to overhaul your incomings and outgoings to maximise money. If you owe any money to current bill providers tackle that first before the rest and once you are up to date with bills go from there.
If you rent you can sign up to a scheme with Experian where they report your rent payments and that helps build a reliable credit history.
It just takes time, patience and perseverance there’s no quick fix and you’ll be at it a while but it’s worth it in the end.