Need To Know
82, including 11 suites.
12pm but flexible, depending on availability. Earliest check-in, 3pm.
Double rooms from $275.31 (£190), excluding tax at 20 per cent.
Rates exclude breakfast (£19 for Continental; £24 for full English), but include free soft drinks in the minibar.
In-room beauty treatments can be arranged, and guests can get 20 per cent off at Beauty & Melody spa a few minutes down the road (+44 (0)20 7723 5028).
At the hotel
Gym, book and DVD library, free WiFi throughout and valet parking. In rooms: Sky HD TV, internet radio with more than 10,000 channels, CD/DVD player with film library, iPod dock, free soft drinks, Jing tea, Nespresso machine and Malin+Goetz products.
Our favourite rooms
If you like watching TV, and like watching it in the bath, book into a Deluxe, Executive or Junior Suite (some have truly massive bathrooms, in case you like to pace up and down while you brush your teeth). We love the original Victorian window in 117, and the mews views from 107. 116 has a wrought-iron window overlooking Great Cumberland Place, and the Welbeck suite has a restored ceiling with some fancy cornicing work, a cubic chandelier and a chaise longue/day-bed hybrid. The Courtyard Studio Suite has its own compact outdoor terrace (very unusual in London).
Your authentic Londoner wardrobe (Savile Row suit for Mr Smith and Mary Quant minis for Mrs Smith) – the Arch’s residential street will make you feel like this prime London postcode is your own.
All rooms have a snazzy button system on the door – with a call for a maid, a doorbell and a ‘zzz’ for do not disturb. If serious sightseeing is on your agenda, book one of the hotel's London Pass packages, which offers access to the city's notable attractions.
Pooches big and small can stay for £15 a night; they'll even be treated to comfortable dog beds and their own feeding bowl. The hotel can also organise dog-sitting, dog-walking in Hyde Park and chef-cooked treats.
Cribs are provided free; extra beds for older children are £60 a night. A babysitter can be drafted in, but you’ll need to give a week’s notice. The hotel's Family Fun package includes a connecting room, passes for London activities and treats for kids.