The 5-star rated London Marriott Hotel West India Quay Hotel in Canary Wharf is just $142 (£93) including taxes and fees for July 31st 2015! Usual rates for this London hotel are around $374, so this a saving of more than 60%.
Plus there may be more dates available.
The $142 rate is for one guest room, with 1 king or 2 doubles or 2 twins/single beds.
Rated 4.5 on TripAdvisor, this hotel is close to many shops, restaurants, pubs and wine bars, and is just 11 minutes from London City Airport.