Whatever it was ran across my foot at a rate of knots and was black or dark brown and about the size of a mouse,and there seems to be a good few of our smaller fish have disappeared + one of our cats caught something that resembles a shrew which is that colour. is it possible this is a water shrew or rat. G.
Most likely a water shrew since they are common all over the UK and they are usually only about 5" (14cm) long. Rats, at least the ones here, are sometimes 4-5 times the size of mice and while they will eat meat...i.e. other rodents, they prefer grains, animal feed, etc.
Here's a website that tells you all about water shrews and their diet. Hope it helps you ID your mystery rodent. http://www.suffolkwildlife.co.uk/ca/fac ... rshrew.htm