Middlesex Guildhall (now the Supreme Court), Westminster.
It is still very common to see places in outer west and northwest London described as being in the non-existent county of Middlesex, as in Greenford, Twickenham, Wembley, etc. In fact the county was abolished in 1965, and only lingered on as a postal address until 1996 when postcodes replaced the need for county names. As many places are no longer in counties, these old names have become superfluous and unnecessary in postal addresses.
Middlesex, being so close to the capital, always had many strange anomalies. Due to boundary changes in the 19th Century the whole southeast of the county, which included the location of the Guildhall and many other administrative centers, were transferred to the London County Council. Prior to that Middlesex bordered the tiny square mile of the ancient City of London. In 1965 the rest of the county of Middlesex became incorporated into the new Greater London authority, except for some small areas in the north and southwest which were transferred to Hertfordshire and Surrey respectively.
The 19th Century county changes meant that Middlesex was the only county to have its guildhall in another county – Westminster in the heart of London. Middlesex Guildhall was used as a high court for years, but is now the location of the newly created Supreme Court (previously the House of Lords performed this function).
Even before abolition in 1965, many areas of Middlesex did not include the county name in postal addresses. Places like Tottenham, Hornsey, Wood Green, Edmonton, etc. had London postal districts. I lived in Wood Green in the 1950s and very early 1960s, and my school/college came under the Middlesex education authority. However our postal district was London N22. No mention of ‘Middlesex’ in the postal address at all.
So many places in the county of Middlesex had a postal address of London before 1965, many administrative offices and the Guildhall were in the neighboring county of London, and from 1965 until 1996 many places in northwest and west London outside the London postal district had to include the non-existent county of Middlesex in the postal address, and this practice still lingers on. Similarly outer London districts formerly in neighboring counties like Bromley (Kent), Romford (Essex), Barnet (Hertfordshire) and Croydon (Surrey) became part of Greater London in 1965, yet due to snobbishness and the reluctance of the Post Office to allocate London postal districts to all of Greater London these former county names still had to be included in postal addresses from 1965 till 1996 even though these places were no longer in those counties. This practice also still lingers on, though a postcode is in fact now sufficient.
All these anomalies spring from the fact that London grew so big it warranted a county and then an administrative region (Greater London) of its own. So where I now live (Battersea) is now part of the London Borough of Wandsworth, but was formerly in the London County Council area which covered inner London, and before that was in the county of Surrey.
Two famous cricket grounds in London, the Oval in Kennington and Lords in St John’s Wood are the home of the Surrey and Middlesex teams respectively although of course the Oval hasn’t been in Surrey for well over a century, and Middlesex hasn’t existed since early 1965.
Many hospitals were named after the county of Middlesex, including the one where I was born in the heart of London just off Oxford Street. Sadly this splendid 1930s building was demolished in an act of wanton vandalism after it was announced it would be converted into a hotel for the 2012 Olympics and thereafter. It would have made a splendid hotel. I presume, since nobody has bothered to tell me, that I can now get my surgical shoe insoles from another hospital.
Going back to the county of Middlesex, the name also still lingers on when referring to the banks of the River Thames in outer West and Southwest London as the Middlesex and Surrey banks.