Tube strikes: are ticket offices almost unused?

News that this week's planned tube strike has been called off might be welcomed by London commuters already struggling with delays and cancellations caused by flooding in the Thames Valley.

However while the unions and London Underground return to the negotiating table, RMT General Secretary Bob Crow made it clear to Tube workers that he and his union "remain firmly against these cuts [to ticket office jobs]".

According to the Prime Minister, the numbers are against Mr Crow. David Cameron told MPs at last week's Prime Minister's Questions that:

"The fact is that only 3% of transactions now involve ticket offices, so it makes sense to have fewer people in those offices."

This isn't correct. We got in touch with Transport for London (TfL), who provided us with the research behind the claim, and what it actually shows is that approximately 3% of journeys begin with a purchase at a ticket office.

To get to this figure, TfL's statisticians looked at the average number of tickets sold at ticket office windows in a four-week period in May, September and October last year, and compared it to the number of trips recorded on the Underground over the same time span.

They found that between 2.6 million and 2.71 million tickets were bought at ticket office windows, while between 93.8 million and 94.8 million journeys were made in the three sample periods. From this they concluded that between 2.74% and 2.88% of trips involved a purchase at a ticket office.

Clearly many transactions pay for more than one journey, including sales of weekly, monthly or even annual travelcards. Similarly top-ups of London's Oyster electronic ticket system, whose pre-paid fares are cheaper than cash, may well pay for more than one trip. More than seven million Oyster cards are in regular use.

TfL itself has been careful in how it has used the figure, saying for example, that "due to Oyster and other innovations, just 3% of Tube journeys involve a visit to a ticket office."

It seems the Prime Minister missed the important distinction between transactions and journeys at PMQs last week, making the level of ticket office use seem lower than it is actually likely to be.

We have asked TfL for the data on the total number of transactions, so that we can properly assess the claim that he did make, and will update once it's been provided to us.

UPDATE (13/02/2014):

TfL have now provided us with the information on the total number of tickets sold at both ticket offices and ticket machines, and from this we can see that the total proportion of transactions taking place at ticket offices is much higher than Mr Cameron suggested. Around one in five ticket purchases took place at a ticket office, much higher than the 3% figure advanced by the Prime Minister.

We'll ask the Prime Minister to correct the record, and we hope that others using the statistic will take care to understand it in its proper context.