Hello , my name is Jack Perhaps I can help you with this problem but first i would have a few questions;
Did this problem happen all of sudden or gradually got worse over the last few days/weeks ?
How old approx. is your samsung ?
Could you please lookup your tv`s model number located on the back cover ?
I have done a reply but I'm not sure if it was sent.
The problem has been happening for quite a while now and does not appear to be getting worse.
The TV is 5 years old.
The model No is LE32A457C1D
O.k then this problem is related to bad capacitors on the power board .
Not sure in the UK but up to last september samsung was repairing this serie of tv `s with that problem for free in north america.
The good news is that this is very repairable and may cost you 40 to 50 pounds to have this done by a repair shop.
If you are into repairing this yourself then i would suggest to simply replace that board , all you will need is a screwdriver.
You can buy that board at the link below;
Hope this help and please take the time to rate my answer positively if that answers your question / does the trick , otherwise do not rate at all , just let me know and we`ll see what can be done.Note that you can reach me here at any time after rating if you have questions or need help replacing that board.