The CLP can choose whether or not to select a candidate on the Labour Party's panel of approved candidates. However, should the CLP select a candidate not on the panel its decision is subject to the National Executive Committee retrospectively satisfying itself that the candidate reaches the standard required to join the panel.
In this and other circumstances the NEC has exercised its power to block a CLPs initial choice of candidate, which has on occasion proved controversial,
Blair and Brown once said no more of the local partys decideing their own favs and started having the at the time more blairite NEC force candidates onto CLPs, which has resulted in the shambles we now have, careerist labour MPs with fuck all connection to their constituency who were straight out of Uni and worked as advisors or interns at westminster.
They have no empathy or understanding of the problems of their constituents, and are just looking at their own jobs.
Thats why the new MPs veer more towards jezza, there was a long hard fought battle with new selections by the unions and CLPs to get the new blood to be more in tune with the party and more people out side of westminster life, hence why Cat Smith, Clive Lewis, Richard Burgon etc were able to get the nomination.
Some of the shit going on in gortons CLP is to do with this, a campaign from the right of the party to bully the left as Kaufmans gonna stand down and they want a parachute candidate not a local councilor or member to get the nomination, (Ed fucking Balls has been muted and if that happens shit will hit the fan)