If I read my RSPB handbook correctly it is either a Chiffchaff or a Willow Warbler. I am leaning towards the latter. The bird had its beak full at the time of taking the image and so no song available? Thank you.
In reply to Robbo:
We spend 90% of net income on conservation, public education and advocacy
The RSPB is a member of BirdLife International. Find out more about the partnership
© The Royal Society for the Protection of Birds (RSPB) is a registered charity: England and Wales no. 207076, Scotland no. SC037654