Simon Calder: Terminal tangle afflicts Britain's busiest airport

Terminal 5 at Heathrow is, by the unchallenging standards of UK airport architecture, magnificent. Not only is the £4.3bn structure a spectacular, spacious celebration of flight – it is also a great place to change planes. Whether you are going from Newcastle to New York or Chicago to Chennai, the all-important "minimum connecting time" is just one hour. In 60 minutes, your bag is transferred in the gigantic sorting office below the terminal, while you are free to explore the shops and restaurants, or simply revel in the space and light "T5" affords.

IAG, comprising British Airways and Iberia, has the building to itself. Before it opened, chief executive Willie Walsh predicted correctly that "The customer experience at Terminal 5 will rival, if not exceed, that at any airport in the world". His colleague, BA commercial director Robert Boyle, promised at the time: "Customers can look forward to a calmer, smoother, simpler airport experience at Heathrow".

Not any more, they can't.

Before the shiny new facility opened, BA's operations were clumsily spread between Terminals 1, 3 and 4. Terminal 5 soon soaked up almost all BA's flights, save for a handful in Terminal 3. The takeover of BMI earlier this year means that, temporarily, BA is flying from all the odd-numbered terminals at Heathrow. I imagined that as soon as BMI was devoured and assimilated, its former home at Terminal 1 would be relinquished.

Wrong. It's back to the bad old days, everyone. Instead of concentrating almost everything at Terminal 5 with a bit of overspill to Terminal 3, BA is moving a wide range of short-haul flights to Terminal 1. The resulting tangle is a nightmare for many passengers on connecting flights to and from UK domestic airports. Belfast to Bangkok? You'll be arriving at 1 and departing from 3. Lusaka to Leeds: that's 5 to 1, the longest inter-terminal journey it is possible make without leaving Heathrow.

All the other UK domestic routes stay in Terminal 5, but some popular European connections – to Basel, Lyon and Toulouse – move to Terminal 1. Add to the tangle the random selection of Eastern European and Far Eastern cities served by BA from Terminal 3, and an ever-higher proportion of BA passengers will find their "minimum connecting time" is extended to 90 minutes, and that they have to take a bus across the airfield. Good luck if your inbound flight arrives late: perhaps inter-terminal sprints could become an Olympic event. Worse still, the chances of baggage going astray rises the more complex the journey it has to make.

BA says that all baggage at Terminal 5 is loaded in containers. The the Airbus jets picked up as part of taking BMI off Lufthansa's hands are designed for manual loading, and cannot be used at Terminal 5. The airline hopes that when the much-delayed Terminal 2 finally reopens (scheduled for 2014), the extra capacity created will allow other carriers to shuffle around so that BA can condense its operations into one-and-a-bit terminals. Will it succeed? Terminology seems as inexact a science as astrology.

Speed to Leeds

Did "Leeds" leap out at you from that selection of cities? It should have done, because after 34 years British Airways returns in December to the Heathrow-Leeds/Bradford route. At present, business travellers from Brazil, China or the US heading for West Yorkshire are currently told they can change planes anywhere they like, so long as it isn't London.

The absence of any connection between Leeds and the nation's capital is as absurd as Cologne having no air link with Berlin, or Bordeaux with Paris. BA is righting this wrong with four flights a day – but the schedule is not exactly generous. The first southbound flight is at 9.25am, the last northbound at 8pm, giving barely nine hours on the ground. Across the Pennines, passengers from Manchester can depart as early as 5.50am, and return as late as 9pm. Who, you may wonder, would ever fly from either Leeds or Manchester for a trip to London? Someone keen to save cash. A flight booked in advance saves £100 or more compared with East Coast and Virgin Trains, who give no deals on rush-hour trains, however early you commit.

Not such a novelty

"New flights" is how BA describes a range of services this winter: Heathrow to Seoul, starting 2 December, to Zagreb beginning a week later and from Gatwick to Barcelona in February. None is new; BA has chosen to resuscitate them. No word yet about which destinations will drop off the map to make room for them.