If you are not working
You can pay up to a maximum of £2880 per person, per tax year into a SIPP
The Government then adds free money on top of this at 20%
No savings accounts are paying 20%, most are paying less than 5%
The only bad point, is that the earliest you can access the money is 55 or 57 depending on your age, due to pension rules
See link
https://www.pensionbee.com/uk