Arsenal's empty seats and near-capacity official figures have been frequently remarked upon

For some West Ham fans, it's not been much fun at London Stadium recently - but at least when the attendances were announced last season many were able to manage a wry smile.

It's a moment replicated in football stadiums across the country as fans hear the attendance, look at the number of empty seats and ask: 'Really?'

Last season, Arsenal were under scrutiny as supporters appeared to stay away from Emirates Stadium during manager Arsene Wenger's final season. Even pundits joked external-link about the club's official near-capacity attendance compared with the gaps clearly visible in the stadium.

But they aren't the only Premier League club where official attendances appeared inaccurate.

West Ham and Man City show discrepancies

BBC Sport sent Freedom of Information requests to the relevant police forces and local councils for all 20 Premier League teams, asking whether they had figures for the actual number of people in the stadium for each game last season.

Most said they did not hold that information, directing us to figures published by the club.

But we received eight responses, relating to seven clubs. At six of those clubs, police and/or council figures differed from the official published attendances.

Although the figures only covered games which the authorities attended, some of the results were revealing:

What we found - the headlines

West Ham: Newham council says the average attendance at West Ham was 42,779 based on the 12 games it attended - which is 12,530 fans fewer than the club's season average figure of 55,309.

Manchester City: Greater Manchester Police's average figures were 7,482 lower than club figures, again based on 12 games.

Southampton: Hampshire Police figures were an average of 4,246 fans lower than figures issued by the club.

Tottenham: Brent Council says crowds at Wembley Stadium were on average 3,740 less than the club's stated numbers.

Chelsea: Hammersmith and Fulham council says its average was 3,505 fans lower than club numbers, based on six games.

Watford: Hertfordshire Police says its average was 2,602 fans fewer than club figures, based on four games.

Manchester United: Trafford Council and Greater Manchester Police both said United's published attendance figures matched its own, based on 12 games.

Average attendances per club Club (% of capacity) FOI (% of capacity) Difference (% of capacity) West Ham 55,309 (97%) 42,779* (75%) 12,530 (22%) Man City 53,274 (97%) 45,792* (83%) 7,482 (14%) Southampton 29,906 (92%) 25,660 (79%) 4,246 (13%) Tottenham 61,843 (69%) 58,103 (65%) 3,740 (4%) Chelsea 40,593 (98%) 37,088** (89%) 3,505 (8%) Watford 20,319 (95%) 17,171*** (80%) 2,602 (15%) Man Utd 73,575 (98%) 73,575* (98%) 0 (0%) *based on 12 games; ** based on six games; *** based on four games

So why the difference?

Most teams in the Premier League choose to publicise the number of tickets sold for a game rather than the number of people actually in the stadium. That means they include season ticket holders who don't attend, and complimentary tickets that are not used.

They are not breaking any rules by choosing this method.

According to the Sports Ground Safety Authority, clubs are required by law to know the number of people attending each game for safety reasons and plan in advance for expected attendances. They do not need to release this information, however, and authorities broadly accept there is sometimes a difference between publicised attendance figures and those obtained by BBC Sport.

Some clubs say they choose to publish 'tickets sold' because the data is more consistent and provides a simpler auditing process.

At Arsenal, the official average was 57,054 at Emirates Stadium last season - 2,813 short of the 59,867 capacity - but the Arsenal Supporters' Trust claims the actual average attendance was about 46,000.

The club disputes that figure, and FOI requests to local police and council could not confirm it either.

Football finance expert Rob Wilson believes publicising 'tickets sold' attendance figures is done for commercial reasons.

He says publishing higher attendance figures could "potentially bring in better sponsors" and generate more interest in season ticket sales by making them appear a "scarce resource".

But Southampton are among those clubs who said there was no commercial gain from doing this as television money was the biggest source of income.

Why do fans stay away?

There are lots of reasons fans stay away from games: cheaper season tickets at some clubs allowing fans to pick and choose games; life or work commitments; games being rearranged for TV.

The health of the club and relative success on the field are also a factor. Both Arsenal and West Ham's reduced attendances last season came when the general mood was less than ecstatic.

Arsenal failed to reach the Champions League for a second season in succession, while some West Ham fans are still disgruntled with the 2016 move to London Stadium, as well as the team's poor form.

But that cannot be said of Manchester City, who won the Premier League by a record margin last season and, based on 12 games obtained by BBC Sport, still showed an average discrepancy of 7,482.

The club, which offers some of the cheapest season tickets in the league and has had record sales for 2018-19, said they were "aware that a percentage of fans are unable to attend matches on occasion, due to a variety of factors often related to individual circumstance".

Do the figures say anything about the health of the Premier League?

The Football Supporters' Federation says there is "an issue of transparency" if clubs only release data on tickets sold.

"Quite often clubs or the authorities will refer to 'occupancy rates' in their arguments," a spokesperson said. "But they are often misleading according to the BBC's research and don't highlight how many fans stay away when matches are rescheduled for TV."

The Premier League rejects that claim, saying occupancy rates in stadiums have remained at 95-96% over the past five seasons despite increasing numbers of games being broadcast live.

But if BBC Sport's research is used as a barometer, albeit from a small sample, it would suggest true occupancy in the Premier League is about 85%.

For the three seasons from 2013-14 there were 154 TV games per season, but from 2016-17 that rose to 168 games for another three seasons - and there will be 200 televised games when the new rights deal kicks in from 2019-20.

The FSF added: "If clubs know the actual number of fans through the turnstile, rather than the number of tickets sold or given away, then there's no reason they shouldn't publish that figure."

But Wilson says there is no real implication for the success or popularity of the Premier League.

"The tickets are being sold whether or not the person turns up to the game," he said. "Where it starts to fall down is if lots of free tickets are being given away to try and pack the stadium.

"[Business analyst firm] Deloitte data said it's about 96% utilisation, but if you take into account [actual] attendances, I would imagine it's still around 90%. Even if it is 85%, that's still pretty healthy."

What else did we learn? The outstanding differences at each club

West Ham's biggest difference in figures was 17,523 fans for the home game against West Brom on Tuesday, 2 January 2018. The official attendance was 56,888 but the council said it was 39,365.

The Hammers' matches against Chelsea and Arsenal in December had a discrepancy of 11,953 (56,953 - 45,000) and 14,721 (56,921 - 42,200) respectively.

Manchester City's largest discrepancy was 15,277 for the visit of Southampton on Wednesday, 29 November 2017 (53,407 compared with 38,130).

For games over the festive period, there was a difference of more than 9,000 fans for City's games against Bournemouth (54,270 - 44,406) and Watford (53,556 - 44,207).

But there was still a difference of 8,687 (54,214 - 45,527) for the 4-1 win against Tottenham on Saturday, 16 December; 4,218 (54,286 - 50,068) for the 3-1 victory against Arsenal on Sunday, 5 November; and 5,524 (54,172 - 48,648) for the 5-0 win over Liverpool on Saturday, 9 September.

Tottenham's largest discrepancy was 8,686 (55,124 - 46,438) for the game with Brighton on 3 December.

Strangely, there were five matches at which Tottenham's published number of tickets sold was lower than the council's attendance figure. There were between 16 and 104 more people in the stadium than the club accounted for. That included the Premier League's record attendance of 83,222 for the north London derby on 10 February 2018. The actual attendance was 83,290.

Four of the six Chelsea matches that Hammersmith and Fulham Council attended were European games where the difference ranged from zero for their last-16 Champions League tie against Barcelona on 20 February (attendance 37,741) to 5,222 (41,150 - 35,928) for their group game against Qarabag on 12 September.

For two Premier League fixtures the difference was 6,345 (41,364 - 35,019), for the visit of Tottenham on 1 April, and 3,096 (41,324 - 38,228) for West Ham a week later.

Chelsea did not want to comment on the differences reported but Trizia Fiorellino of the Chelsea Supporters' Group rejected the Premier League figures. It is also understood attendances are capped at a lower level for European games and to make room for TV equipment.

Hammersmith and Fulham Council said they collated the figures in liaison with the club.

At Southampton, who only achieved Premier League survival on the last day of the season, the biggest discrepancies came towards the end of the campaign, according to Hampshire Police.

The Saints said their attendance for Chelsea's visit on 14 April was 31,764 but police figures show 6,945 fewer fans at St Mary's. There was also a difference of 6,799 (31,778 - 24,979) for the home game against south-coast rivals Bournemouth.

At Watford, only four attendances were obtained via Hertfordshire constabulary - for home games against Liverpool, Brighton, Manchester City and Arsenal.

But in each case, fewer fans attended than were advertised - amounting to an average discrepancy of 2,602 per game. The biggest difference was for Brighton, amounting to 3,568 (20,181 - 16,613).

'Every empty seat is a tragedy' - what fans and clubs said

At Emirates Stadium, where there is a long waiting list for one of 48,000 season tickets, the Arsenal Supporters' Trust (AST) says publishing attendance figures would "highlight the scale of empty seats and perhaps put more emphasis on it being addressed".

The AST's Tim Payton says every empty seat is "a tragedy for those who want to watch but can't get in".

Payton believes Arsenal could tackle the problem by introducing an app to improve ticket resales, although it is understood 60,000 tickets were sold through the club's ticket exchange last season.

Other clubs are attempting to improve that type of facility, too, including West Ham.

The Hammers' 2016 move to London Stadium from Upton Park has been beset by problems and Paul Turner of the West Ham United Independent Supporters' Association calls the attendances "fake news" and a "face-saving operation" for the club's owners, who he claims are still trying to prove to some fans that the move was a good idea.

With a court case to come in November, at which the club will attempt to boost its capacity, Turner says the publication of inflated attendances "helps their narrative".

But West Ham claim the discrepancy is because they offer some of the cheapest season tickets in the Premier League, and the cheapest among the top-flight's London clubs. As a result they have 50,000 season ticket holders, with 10,000 junior season tickets among them.

Meanwhile, Southampton season ticket holder Nick Illingsworth has questioned police figures given the biggest discrepancies came when they were battling for survival against Chelsea and Bournemouth.