Considering the mass exodus of Dr's abroad, who exactly do they expect to do this. The only way to achieve this is to improve conditions, pay, and invest in the training of new Dr's.
When New Labour introduced the 48 hour target to see a GP, the vast majority of GPs 'met' the target by closing down their phonelines as soon as they ran out of appointments. In the process, they turned the 48 hour target into a 24 hour target because otherwise they'd only have been able to open the phoneline every other day.
It was very bad back then. It's much worse now because the NHS was at least relatively well-funded under Blair.
Not that they're announcing this because they think the policy will work, obv. Just doing their best to make sure the voters blame everyone but them.
[The link is to a video of an election Question Time audience haranguing Blair about the foolishness of this target.]