As the Official Photographer to many Federations and Associations I get to work in Westminster on a regular basis. Events' will most likely be held in one of four popular event venues. All are stunning Venues to work in offering superb opportunities to get great event pictures.
House of Commons / House of Lords
Quoting from the https://www.parliament.uk/visiting/venue-hire/ The location is steeped in history and nestled in the heart of London, the Palace of Westminster stands as a timeless emblem of tradition and modernity. Comprising both the House of Commons and the House of Lords, we offer a unique and iconic setting for your next event.
From personal experience I always have a positive feeling about working in one of their many function rooms. In particular as a photographer I enjoy the riverside rooms. Not only do they offer a great spaces, wonderful food and friendly staff the location is awesome. Over looking the Thames you get a great view of the London Eye and Westminster Bridge. Guests love to take selfies and it offer me some cool professional images for my clients.
One Great George Street
Quoting form https://www.onegreatgeorgestreet.com/ It's a central London conference centre, event and wedding venue in Westminster. Set in a magnificent Grade II listed, four-domed, Edwardian building the conference centre is very close to the Houses of Parliament, Westminster Abbey, Buckingham Palace and St James's Park.
The rooms are big and grand with fabulous window light. Perfect for business events and weddings. I have been lucky enough to photograph both many times. Not only am I a business / corporate photographer I'm also a wedding photographer.
QEII Centre
Quoting from https://qeiicentre.london/ it is a trusted destination for conferences in central London for almost 40 years, the QEII Centre has all the facilities you need. Take advantage of our superb location, flexible layouts, first-rate AV and catering and expert event managers. This venue is massive and I hvae shot many events here. One was running with several presentations at the same time every 30 mins. YOu need to be fit and agile to get round five events every half hour throughout the day!