The UCL is located just south of Euston Road, close to Euston, Euston Square and Warren Street underground stations. A selection of useful maps can be found at http://www.ucl.ac.uk/maps/
The postal address is:
Department of Physics & Astronomy,
University College London,
There are 5 airports serving London, none of which is very close to UCL. Instructions for getting here from each of them are given below. Please then look at the local maps or streetmap for directions from the tube stations to UCL. Your first port of call at UCL is likely to be the Pearson Building where the conference will be taking place. For details click here.
From London Heathrow (LHR)
A simple option here is to take the Underground Piccadilly Line
(cost about 4 GBP) all the way to Russell Square. However, the journey
time is ~1¼ hours.
A faster route and one which ends closer to UCL is to take then Piccadilly line to Green Park and change to the Victoria Line (northbound) to Warren Street.
A more expensive (cost about 15 GBP plus 2 GBP tube) alternative is to take the Heathrow Express to Paddington (detailed prices here) and change on to the underground there. From Paddington you would get the Underground (Circle line) to Euston Square.
From London Gatwick (LGW)
The simplest way from Gatwick is to take the Gatwick Express to Victoria, then take the Underground (Victoria line) to Warren Street.
From Luton (LTN)
Take the free shuttle bus from the airport to Luton Airport Parkway station, then take a train to either Kings Cross or St. Pancras. It is usually quicker to buy a train ticket at the airport as there can be long queues at the ticket office when a bus unloads at the station.
From Stansted (STN)
Take the Stansted Express to Tottenham Hale and change on to the Underground (Victoria line) to Euston.
From London City (LCY)
Take the Docklands Light Railway (DLR) to Bank and change on to the Underground (Northern line) to Euston.