Some of the problems stem from the natural barriers that exist within London, which cannot feasibly be crossed by any constituency even though mathematically it would make creating constituencies easier, especially without split wards.
There are two important barriers in North London, for example, which are the River Lea (the western boundary of Essex, in effect), a natural barrier, and the A5 dividing Harrow and Barnet. Although you can actually walk from Harrow to Barnet and back (meanwhile, there are only two roads crossing the Lea from Enfield to Waltham Forest, and the River Lea is a clearer dividing line) there are no trains going directly from any part of Barnet to Harrow and only a few bus routes connecting that area, so I think it is best if Barnet and Harrow are kept separate.
Given the considerable variation in ward sizes, especially among boroughs no longer sticking with the 3 members per ward system (most London boroughs still stand by it, although they are departing from it overall with each successive boundary change affecting one or more London boroughs), and the problems this causes when creating constituencies within the narrow range of allowable electorates, it is best to create groups of boroughs to create workable constituencies with at least some viable connections with each other, and to make sure as few cross-borough constituencies as possible are created.
I will start this section with North East London, which covers the London boroughs which were all once in Essex and which are east of the River Lea. This comprises the boroughs of Waltham Forest, Redbridge, Barking & Dagenham, and Havering. Ward size disparities are an issue, particularly between Barking & Dagenham and Havering, so I believe ward splitting is necessary. If the maps I give on this blog show a constituency which unsplit is over quota or under quota, I will state which polling districts of which wards are added and what those polling districts comprise.
Due to the issues of public transport connections, which most reliably and most frequently go east in these parts, it is necessary to preserve Ilford South and split Ilford North to resurrect Wanstead & Woodford (abolished in 1997), the only part of this area with a reliable north-south public transport connection. The large average size needed for constituencies here also requires ward splitting, but this can be kept to a minimum; if the variance allowed under the 2011 Parliamentary Constituencies and Voting Reform Act was 10% rather than 5% this exercise would be far easier even with the reduction in seats.
My alternative proposals for North East London are:
Wanstead & Woodford succeeds Ilford North in practice. It contains polling districts FA3 and FA5 of Fairthorpe ward which are both west of Fencepiece Road, making its actual electorate 78,210.
Chingford & Walthamstow North succeeds Chingford & Woodford Green. Of High Street ward it does not contain polling district ND which is east of Palmerston Road, meaning its actual electorate is 77,668.
Leyton & Walthamstow South succeeds Leyton & Wanstead. It has polling district ND of High Street ward, making its actual electorate 77,864.
Upminster succeeds Hornchurch & Upminster, and apart from the fact it includes Rainham ward, restores the pre-2010 constituency of Upminster.
Romford & Hainault succeeds Romford. It contains polling districts FA1, FA2, and FA4 of Fairthorpe ward which are east of Fencepiece Road, and in Chadwell Heath ward loses polling district QC, covering the southeastern portion of that ward. This means its actual electorate is 77,274.
Hornchurch succeeds Dagenham & Rainham in practice and reunites the town of Hornchurch to a significant extent. It has polling district QC of Chadwell Heath ward, making its electorate 77,768.
Barking & Dagenham succeeds Barking.
Ilford has the exact same boundaries as Ilford South; as Ilford North no longer exists in this plan and as the entire actual town of Ilford is in the current Ilford South constituency, I believe this name change makes sense.
Next in this series: East London.