How to save in UK without facing US taxes?

Hi,

I'm a US citizen married to a UK citizen, living in the UK. I am looking to save money - looking currently at £2-3k pa - with a view to retirement in 30 years time. I will not need the money until then. I could put it into a cash savings account but rates are very low. I am aware that ISAs are taxed punitively by the IRS, so can't see this being a worthwhile way to save.

So I'd appreciate your help. Is my best option for saving this money to do so with a pension? If so, I would plan either to make AVC payments into my workplace pension or to set up a separate personal pension - would both of these options enable me to save my money without facing punitive IRS taxation now?

Also, we are not yet sure whether in 30 years time we will be living in the US or UK. Would it be fairly straightforward to receive the resulting pension whichever country we are living in, without facing a punitive tax bill at that stage?

Huge thanks for any advice!

My understanding is cash ISAs are treated like any other savings account by the IRS.  It's the stocks&shares ISAs that you want to avoid.

Assuming my understanding about the IRS treatment is correct, if you're under 40yo, have you considered a Lifetime ISA?  https://www.moneysavingexpert.com/savings/lifetime-isas/

Cash ISAs are treated like regular interest bearing savings account by the IRS, but their returns are rubbish as well at present.

I would go with a pension plan, but if you go with an employer pension plan my understanding is that it becomes a Foreign Grantor Trust if you contribute more than your employer.  Still no income tax I believe on an FGT but it has to be reported as part of your tax return each year.  Our son pays into a UK company pension plan, matching his employer’s contribution. He reports it as part of FBAR but not in his IRS filing.

Thank you both!  The Lifetime ISA is a helpful option to know about. Reading that webpage it does seem that the pension is usually preferable for retirement. So if I can work out how to pay into the pension without getting into complicated IRS situations I'll go down that route. Thank you for the FGT information. Some more thinking and research to do...