Is this is a parasitic wasp, which I found in Blackpool Lancashire?
Yes it is ! If you look closely at the wing patterns, they are characteristic of the Ichneumonidae family, as you can see below*. This family contains thousands of species which all are parasitoids. Species identification is very tricky for this family, but the patterns on the abdomen (2nd and 3d strips are yellow, the others are black, yellow spot at the tip) and on the tibia (yellow strips) are very characteristic of the species Ichneumon stramentor, which parasitizes caterpillars.



Based on the width of the abdomen, this is probably a female (ovipositor is not visible for this species).

It's actually quite common in the UK (they live in habitats such as hedgerows or woodlands), but not so frequently seen on windows!



*Image source : DrawWing.org 

Derived from: Comstock J.H.
(1918) The wings of insects. The Comstock Publishing Company, Ithaca, N.Y.