What a disappointment.

The cancellation of the fifth Test between England and India denies a pulsating series a fitting climax, ends the men's international summer on a whimper and, more importantly, robs the paying public.

The fallout from the non-event at Emirates Old Trafford has begun, even if the tone between England and India is one of diplomacy.

Amid the questions, some can be answered, while others will take time to be played out to a conclusion.

What happened?

India head coach Ravi Shastri tested positive for Covid-19 during India's fourth-Test win last week, forcing three other staff members to isolate.

When another member of the backroom team, a physio, tested positive on Thursday, India cancelled training.

Although all players tested negative and the England and Wales Cricket Board (ECB) said the Test would go ahead, discussions that went on through Thursday night ultimately led to the match being cancelled two hours before it was due to begin at 11:00 BST on Friday.

The ECB initially said India had forfeited the match, only to retract that statement. Where that leaves the series - India were 2-1 ahead - is up in the air.

Almost 80,000 tickets had been sold in advance for the first four days, with fans set for a full refund.

However, many will have taken time off work, booked travel and accommodation, and been anticipating the spectacle of a final Test with the series on the line. A refunded ticket will not take away the disappointment, inconvenience or anger.

The cancellation of this match will also leave a bitter taste for the wider cricketing world and possible huge financial implications for the ECB, Old Trafford, broadcasters and sponsors.

Was it the right decision to call it off?

That depends who you ask.

There are a few things to keep in mind, too. On top of the fact no India players tested positive, they are travelling with an enlarged squad - 21 players - to deal with Covid issues.

However, they have been on tour since June. While the restrictions placed on players have not been as harsh as during other series, they can still not enjoy the same level of freedom as the wider public.

England have been in a similar situation. In December, their one-day series in South Africa was postponed partly to protect the players' mental wellbeing after it was thought Covid had infiltrated the team, even if two positive tests ultimately came back negative.

"You can't be flippant or light-hearted about issues of mental health," ECB chief executive Tom Harrison told BBC Test Match Special on Friday.

"When Covid creeps into an environment, it can accelerate very quickly. We've seen that ourselves in the past."

The majority of the India players are travelling with their families, perhaps creating a concern that coronavirus could spread to partners or children.

"Most of them are here with their families," said former India wicketkeeper Deep Dasgupta. That is one of the biggest concerns for them. What if both of the parents tested positive?"

Still, former England captain Michael Vaughan said India had a responsibility to fulfil the fixture, just as England had a duty to in South Africa.

"I felt at the time England let South Africa down," said Vaughan. "England flexed their muscles back then and I believe India have flexed their muscles.

"I honestly feel Indian cricket has let the English game down."

What happens now?

In the short term, probably very little.

The India players, along with some from England, will leave for the Indian Premier League (IPL), which restarts on 19 September (more on this later).

The biggest question is how the Test series will be resolved. That the ECB quickly retracted their assertion India had forfeited the match is important, because a forfeiture would give England the match, a share of the series and World Test Championship points.

The exact nature of how and why the match was called off will also have financial implications for the ECB, related to insurance.

"The result of the match may appear unimportant but, with millions of pounds of compensation to be determined, it needs to resolved," said BBC cricket correspondent Jonathan Agnew.

Harrison said the issue of the result is "not one for today", and that it will be ruled on by the International Cricket Council (ICC).

The BCCI has offered to reschedule the match, although that is more likely to be a standalone Test, rather than the fifth match in this series.

As for when that could be played, India are due back in the UK next summer for three Twenty20 and three one-day internationals.

But the rest of England's schedule is packed, so it could mean rearranging other fixtures or separate red-ball and white-ball teams playing simultaneously.

Isn't it all about the IPL?

The elephant in the room.

The IPL was postponed amid rising coronavirus cases in India in May and is due to resume in the United Arab Emirates next weekend.

If that wasn't the case, would there have been scope to delay the fifth Test? It is also worth noting that the BCCI informally requested

to tweak the schedule of the series to help accommodate the IPL, although there is no suggestion that is linked to the cancellation of the finale.

The IPL is a financial behemoth, not only for the players and the BCCI but also the global game.

"The BCCI would have been scared to death that the players wouldn't have been able to get over and play in the IPL," said Vaughan.

"Players will be petrified of picking up the virus and having to miss IPL games.

"It's all about the IPL money. The ECB will not want to fall out with the BCCI. They are the powerhouse."

However, Harrison said drawing any link between the IPL and the cancelled Test is "unfair".

"This is not a situation that has been recreated by the rescheduled IPL," he said. "I fundamentally do not believe that for one second."

What about the Ashes?

Ah, yes. England's next Test series, itself under a cloud of Covid-related doubts.

Some England players have indicated they may pull out

of the tour if their families cannot join them in Australia.

On Wednesday, captain Joe Root said the lack of information is making planning "very difficult".

Australia has some of the strictest Covid-19 protocols in the world. The five Tests in December and January are due to be played in five states, each of which have their own rules, adding a further layer of complication.

Postponing the series is unlikely, although which England team fulfil the tour is currently unclear.

"Let's hope that we can get all of this agreed and take our best team to Australia," said Harrison.

"Let's have a great experience over there and bring back the Ashes."