Labour members in both Streatham and Wimbledon local parties last night voted to switch from a general committee (GC) delegate structure to holding all-member meetings (AMMs).

The two Constituency Labour Parties (CLPs) have become the first in London to opt for the alternative arrangement since conference passed a rule change that made swapping the structure of CLP-wide meetings easier.

Most London CLPs currently have a GC in which only representatives sent by branches, affiliated societies and unions are allowed to vote in monthly CLP meetings. But since September, several parties have been considering the switch to a one-member-one-vote system.

This decision now requires only a simple majority of members attending a special AMM to vote in favour of it. Bermondsey and Old Southwark, Hampstead and Kilburn, Holborn and St Pancras have all considered the change but no London CLP has voted in favour under the new rules – until now.

In Streatham, members voted by a narrow margin – 190 to 183 – for AMMs following a battle between rival factions, which partly played out through LabourList articles that were widely distributed within the CLP.

Labour First organiser and local branch chair Matt Pound argued that AMMs would make CLPs with such large memberships “structurally flawed and ineffective”, and pointed out that left-wing group Campaign for Labour Party Democracy (CLPD) used to oppose them.

In a response piece, fellow Streatham officers Axel Landin and Andrew Collins said AMMs would be more democratic, and have been positive in large London CLPs Battersea and Cities of London and Westminster.

On the day of the all-member meeting, activist and commentator Owen Jones urged Streatham Labour members to attend and vote for “a real say in the local party” in a tweeted video.

Are you a member of @StreathamLabour? If you think that all members should have a real say in the local party, vote at tonight’s meeting >> pic.twitter.com/0BJtivrL2e — Owen Jones🌹 (@OwenJones84) January 31, 2019

Activists on the Labour left believe that holding AMMs will make engaging and attracting new members easier, while Corbynsceptics fear that the new system will bolster threats of deselection against local MP Chuka Umunna.

LabourList understands that Wimbledon voted in favour of AMMs by a larger margin, but the turnout was low. It is a Tory-held seat, where Stephen Hammond has a 5,622 majority.