3 objects flying in triangular formation

we were stood in the garden and noticed 3 objects that were pretty low flying in a triangular formation.they were traveling east to west between 6.30 pm to 6.40pm. it was partly cloudy but these were below cloud, but increasing there height. they also flew in a triangular formation, then they flew in a straight line. never touching eachother. there was no noise from them. as good as my eye could see i watched them ascend in to cloud or maybe just to far in the distance i could see. we live in wolstanton, newcastle under lyme, staffordshire, united kingdom. very interested to hear, if anyone else witnessed this and maybe shed some light for me.