Dark Bush Cricket (Pholidoptera griseoaptera)
That said, the colouring can vary from a chestnut colour to almost black, the female usually paler than the male although this female I photographed is pretty dark in colour.
This insect can be found in any rough vegetation such as hedgerows, woodland scrub, roadside verges and quite often in garden shrubberies.
They do not really 'sing', making a single high pitched squeak repeated intermittently. They do 'sing' by day but are far more active in the evening and if you have young ears you can quite clearly hear them.