i am traveling to lanzarote in aug and i come home on the 6th of sep but my passport runs out on 27th of sep can i still travel with this or do i need a new passport
Although the Canary Islands are outside the EU, they come under Spanish jurisdiction and the same rules apply as for mainland Spain.
As long as you hold a British passport (or a passport from another EU country), you'll have no problems. EU passports are valid throughout all 27 member countries up to (and, in some cases, beyond) the specified date of expiry.
Contact your airline about this. Some airlines require passengers to have 3 or 6 months validity on a passport beyond the date of return, even for EU citizens travelling within the EU. I think this is in case an aircraft has to divert to a non-EU country in an emergency, like North Africa, but I'd call them anyway.
I went to Lanzarote last year on a passport that had just one month left. Had no problems at all, apart from a Customs lady when I got back to the UK who kindly reminded me that it was due to expire (as if I didn't know).