Sherlock Holmes Society of London: We meet at Goodge Street Station, Tottenham Court Road. Richard checks his notes, while Philip Porter & Catherine Cooke converse (photo by Roger Johnson)
Sherlock Holmes Society of London: The photographer is rather taken with this impressive dome on the corner of Chenies Street, on the opposite side of Tottenham Court Road (photo by Roger Johnson)
Sherlock Holmes Society of London: Everyone has arrived. Richard Burnip explains the relevance of this area to the case of the Blue Carbuncle (photo by Roger Johnson)
Sherlock Holmes Society of London: Philippa Kelly has a question. The others seem uncertain of Richard Burnip's response (photo by Roger Johnson)
Sherlock Holmes Society of London: We have moved a few yards further south, to the corner of Goodge Street. This is where Mr Henry Baker lost his hat and his goose (photo by Roger Johnson)
Sherlock Holmes Society of London: A little way along Goodge Street, we turn left into Whitfield Street, and stop at Whitfield Gardens. It seems likely that Henry Baker lived in this area (photo by Roger Johnson)
Sherlock Holmes Society of London: Perhaps Mr Baker rented rooms in Colville Place, which runs alongside Whitfield Gardens (photo by Roger Johnson)
Sherlock Holmes Society of London: Our guide Richard Burnip has a store of entertaining facts and factoids about this area of Bloomsbury - which is known as Fitzrovia (photo by Roger Johnson)
Sherlock Holmes Society of London: British Transport Police is a national specialist force that polices the railway network of England, Wales and Scotland - so shouldn't this depot be at a railway station rather than in Whitfield Street? (photo by Roger Johnson)
Sherlock Holmes Society of London: From Whitfield Street we emerge into Percy Street, where a blue plaque commemorates the actor Charles Laughton. He never played Sherlock Holmes, but he was the first actor to play Hercule Poirot (photo by Roger Johnson)
Sherlock Holmes Society of London: In Percy Street, Auberon Redfearn and Philip Porter listen intently to our guide Richard Burnip. So do the rest of us, of course (photo by Roger Johnson)
Sherlock Holmes Society of London: Crossing Tottenham Court Road, we make for Bedford Square, where a plaque celebrates another great actor, Johnston Forbes-Robertson - who could have made a fine Sherlock Holmes (photo by Roger Johnson)
Sherlock Holmes Society of London: In Bedford Square Richard Burnip has more interesting information for us, though the picture doesn't quite capture that, sadly (photo by Roger Johnson)
Sherlock Holmes Society of London: During his brief spell as an ophthalmologist, Conan Doyle lived in Montague Place. All the houses are gone now, and on the one side are the King Edward VII Galleries of the British Museum (photo by Roger Johnson)
Sherlock Holmes Society of London: However, the houses in nearby Montague Street are recognisably the same as they were in the mid-1870s, when Sherlock Holmes first moved to London (photo by Roger Johnson)
Sherlock Holmes Society of London: Michael Harrison discovered long ago that a Mrs Holmes lived in Montague Street. If she was a relation, perhaps Sherlock took rooms in her house (photo by Roger Johnson)
Sherlock Holmes Society of London: If the young Sherlock did take rooms for a while with Mrs Holmes, this is where they lived - no. 24 Montague Street (photo by Roger Johnson)
Sherlock Holmes Society of London: Having passed two candidates for the "real" Alpha Inn, and crossed High Holborn, we make our way along Endell Street, in the direction of Covent Garden (photo by Roger Johnson)
Sherlock Holmes Society of London: Not notably Holmesian, but delightfully Victorian, here in Endell Street is the former Lavers & Barraud Stained Glass Works (photo by Roger Johnson)
Sherlock Holmes Society of London: Just a few yards further on in Endell Street is a plaque commemorating the stained glass artist Nathaniel Westlake, who designed for Lavers & Barraud - and eventually bought the firm (photo by Roger Johnson)
Sherlock Holmes Society of London: In Bow Street, we stand outside the Royal Opera House, Covent Garden, where Holmes proposed to attend a Wagner night (photo by Roger Johnson)
Sherlock Holmes Society of London: Opposite the Opera House is the former Bow Street Police Station & Magistrates' Court. The splendid building now houses a hotel and a museum (photo by Roger Johnson)
Sherlock Holmes Society of London: At this corner of the building was the entrance to the Bow Street Magistrates' Court (photo by Roger Johnson)
Sherlock Holmes Society of London: Our tour ends opposite the NoMad Hotel & Bow Street Police Museum. Some will look for a poulterer at Covent Garden. Some will want a refreshing drink. Some will head for home. Thank you, Richard! (photo by Roger Johnson)