Rome or London?

Neither city is built for a beach vacation, but Rome comes closer. Ostia's dark volcanic sand is half an hour away by suburban train, and in high summer the sea is warm enough for a proper swim, though the lidos fill with Romans at weekends.

London's nearest coast is Brighton's pebble beach, an hour away, where the Channel stays bracing even in late summer. The city's real swimming is in fresh water: the lidos at Brockwell Park and Parliament Hill and the Hampstead Heath ponds, which Rome has nothing to match.

Both are excellent places to eat, but in opposite ways. London's strength is range: Bangladeshi cooking on Brick Lane, Turkish grills in Green Lanes, Punjabi food in Southall, Borough Market and a large fine-dining scene, with the pub and the Sunday roast as its own rituals.

Rome cooks almost only Roman food, and cooks it with conviction: the four classic pastas, Jewish-style artichokes in the Ghetto, offal in Testaccio, and pizza al taglio and supplì on the street. The best meals are in plain trattorias in Trastevere, Monti or Testaccio, and eating well costs noticeably less than in London.

These are two of the richest cities anywhere for sightseeing, and a week in either leaves plenty unseen. London's treasures are mostly gathered into great collections, such as the British Museum, the National Gallery, the V&A and the two Tates, nearly all of them free, with the Tower and Westminster Abbey between them.

In Rome, the history is the city itself. The Forum, the Pantheon and the Colosseum stand among the traffic, and Caravaggios hang in ordinary parish churches. The Vatican Museums and the Borghese Gallery are world-class too, but they charge for entry and the queues are long.

London has far more going on after dark. Soho runs late with cocktail bars and a long-established gay scene, the east from Shoreditch to Dalston has the clubs and warehouse parties, and Brixton and Peckham add big venues, with thousands of pubs everywhere.

Rome's nights are spent outdoors: aperitivo, a long dinner, then a glass in the lanes of Trastevere or a small wine bar in Monti. There are clubs around Testaccio and Ostiense, but they are not a reason to come, so anyone who wants to dance until morning is better off in London.

London's outdoors is mostly inside the city: big central parks such as Hyde Park and Regent's Park, deer among the ancient oaks of Richmond Park, the view over the skyline from Hampstead Heath, and Kew's gardens. Beyond it, the chalk downs an hour out by train are gentle walking country.

Rome's best outdoor day is a bike ride down the Appian Way past tombs and aqueduct arches, and the land gets wilder further out: the crater lakes of the Alban Hills, then the Apennines about ninety minutes away for hiking or winter skiing. London's walking weather is often grey and damp, while Rome's summer heat makes midday outings hard.

Both are first-rate bases, but the outings have a different flavour. From London, trains reach the colleges of Oxford and Cambridge in about an hour, along with Windsor, Bath, Stonehenge and Canterbury, a tour of English history through cathedrals, castles and a Georgian spa town.

Rome's trips go deeper into the ancient world: the excavated port of Ostia Antica, Hadrian's Villa at Tivoli, the Etruscan tombs of Tarquinia, and hill towns such as Orvieto and Civita di Bagnoregio. Fast trains also put Florence and Naples within about ninety minutes, so two more great cities can be a day out.

London is much the easier city with children. The Natural History Museum, the Science Museum and the Young V&A are free, the parks have playgrounds and boating lakes, and the zoo, the aquarium and Legoland Windsor fill the other days. Long distances and Tube stations with only stairs are the main nuisance.

Rome welcomes children at every trattoria table but gives them less to do. Its sights are aimed at adults, the queues are long, and cobbles, traffic and summer heat tire small legs quickly. The Bioparco and the rowing boats in Villa Borghese, gladiators and daily gelato are the main rewards.

London's transport network is far more complete. The Underground, the Elizabeth line, the Overground, the buses and the Thames riverboats all work with one contactless card, so you can reach any corner of a very spread-out city. The price is crowded rush hours and long station corridors.

Rome is a city to walk. The centre is compact, and the stroll from the Colosseum past the Pantheon to Piazza Navona is part of the pleasure. But the metro skirts the historic core, buses stall in traffic, and cobbles, scooters and heat make a day on foot tiring.

London is the better shopping trip by a wide margin. It covers every level, from the luxury houses of Bond Street and the bespoke tailors of Savile Row to department stores such as Harrods, Liberty and Fortnum & Mason, which are sights in their own right. Markets from Portobello Road to Columbia Road add to it.

Rome's strengths are narrower: the Italian fashion houses on Via Condotti below the Spanish Steps, small boutiques in Monti, and good leather goods and handmade shoes. There is little department-store tradition, and the main tourist routes are heavy on souvenirs.

Neither is cheap, but London costs more at almost every turn. Hotel rooms, meals, pub rounds and theatre tickets add up fast, and the main relief is that the national museums and galleries are free.

In Rome it works the other way round. The big sights charge entry, but daily life is kinder, with espresso drunk standing at the bar, pizza al taglio, simple trattoria lunches and free water from the street fountains. In both cities, a central room is the biggest single cost.

For theatre and concerts, London is in a different league. The West End, the National Theatre, the Globe and fringe stages above pubs offer a choice of drama every night. On top of that come the Royal Opera House, five major orchestras, the Proms at the Royal Albert Hall and jazz in Soho.

Rome's offer is smaller and mostly musical, since theatre is in Italian. Its highlight is summer opera among the ruins of the Baths of Caracalla. The Santa Cecilia orchestra at the Auditorium Parco della Musica and sacred concerts in churches fill the rest of the year.

Neither city is a place to unwind, but London keeps its bathing indoors and in town. Historic public Turkish baths survive in Bayswater and at Ironmonger Row in Islington, with steam rooms and plunge pools under tiled vaults, and the grand hotels of Mayfair and Knightsbridge run full spas. For real thermal water, Bath is about an hour and a half away by train.

Rome's ancient baths are ruins, and its warm water is out of town: the sulphurous pools at Bagni di Tivoli and free open-air hot springs around Viterbo. The centre is loud with scooters and crowds, so calm comes from Roman habits instead, a long lunch, the evening passeggiata and the quiet of the Aventine.