garden tap/hose has poor flow?

I've got a garden tap that has poor flow; it's not drastically poor but not as heavy as it should be. I removed the hose from the tap because i thought it may be the tap itself that may be restricted but the flow from the hose is identically poor. The other end of the hose goes inside the house via the brickwork and uses the 'cut into the pipe' type connections on the cold water feed just off the rising main.
Any ideas why the flow is poor?
I need to increase the flow to effectively use a pressure washer.
thanks for any help.

Perhaps your mains water stopcock is not fully open, have you a good pressure at your kitchen tap.
I,d also consider what has happened to the small disc that is made by these 'cut into the pipe' type of fitting.
Could you not remove the outside tap then open the inside valve to flush out the disc if it's loose.
Or close main stopcock and remove both outside tap and inside valve to see if the formed disc has not been cut off but restricting the flow.
Having said all that I don't think it does affect a pressure washer but next time I use mine I will partially close my tap to see what if anything happens.

vijay also see yor first pot on this subject which is here