I think there are more fundamental problems with the income tax system than taxation of savings interest over £1000. It needs wholesale reform and simplification.
Yes HMRC have been unfit for purpose for at least 15 years, I had dealings with them (painful to say the least) about business expenses around 15 years ago.
My company ended up sending me to an external accountant who did work for us, I went in with all my P60's and letters etc, he read everything and then said that he knew HMRC was a total mess but i've not seen incompetence on this scale before.
I'd get a letter telling me I owed them £500 then 2 days later another saying it was £150, a few days later apparently they owed me £50 then they settled down and claimed I owed them sums between £5 and £10 but couldn't seem to actually work it out

How much did it cost for a bunch of fuckwits to process and chase / send out letters for a bit of chump change which was fundamentally wrong as I didn't actually owe them a penny.
In the meantime they seem to leave the larger multinational tax dodgers like Vodafone; Starbucks and Amazon alone

I believe quite a few years ago a decision was made to cut staff numbers in a bid to save money, what wasn't factored in was that employing less staff meant they couldn't chase and claw back as much money or at least they couldn't chase the big numbers just go after the small guys for a few quid
So often these decisions on "cost saving measures" end up costing far more than they save
