In 2007, the Duke of Bedford evicted the beloved St Margaret’s budget hotel after a residence of half a century. As its devotees howled, the premises were swiftly converted to an expensive boutique hotel. The St Margaret’s operators, the eccentric but dedicated Marazzi family (“We were swindled!” one exclaimed to me), decamped nearby to the Celtic, transforming a bleak guest house (near the British Museum and the Tube to Heathrow) into their new, charismatic budget citadel. Few other budget hoteliers put as much heart into making sure guests are acclimated to London by answering questions, obliging special dietary requests, and filling bellies with a cooked breakfast that’s so enormous (try the banana yogurt) that lunch might become optional. To keep attracting longtime regulars, the Celtic retains the top-value features that made Maggie’s a quirky stalwart: rooms do not have TVs or phones, furniture is endearingly mismatched, and the lounge is a hub for socializing with fellow guests. Add £6 to £22 if you don’t want to share shower or toilet. You must book directly.