The present disclosure provides antibody sequences found in antibodies that bind to human CD25, in particular an anti CD25-a-674 antibody which do not block the binding of CD25 to IL-2 or IL-2 signalling. The claimed antibody binds to the epitopes: YQCVQGYRALHRGP (150 to 163) or SVCKMTHGKTRWTQP (166 to 180) on CD25 Antibodies and antigen-binding portions thereof including such sequences can be used in pharmaceutical compositions and methods of treatment, in particular for treating cancer.