Did that ball go in? The hows and the whys of technology on the goal-line

After Mata's 'goal' on Sunday, few doubt the need for it. But with chip or camera? When? Where? Sam Wallace gives a few answers

Q: Why are we still waiting for goal-line video technology?

A: The Football Association has been pushing for it with Fifa for the past 10 years. The penny finally dropped after Frank Lampard's "goal" against Germany in Bloemfontein at the 2010 World Cup finals was not spotted. Since then Fifa has been on board.

Q: So how come that was almost two years ago?

A: The problem is technology. For all the table-thumping demands to "get it done", the system has to be perfected first. The spec is that the referee should be told, via his headset, within a second of the incident, whether the ball has crossed the line or not. It is not as simple as it seems.

Q: Hasn't the technology been tried before?

A: Yes, there were test systems in place at the Under-17s World Championship in Peru in 2005 and the Club World Cup in Japan two years later. On both occasions the systems failed.

Q: How close are we now to something that works?

A: The final two contenders to provide goal-line technology from an original field of eight will begin their second and final phase of testing before the end of this month and run through into the next. One is Hawk-Eye, which is already well known from the worlds of tennis and cricket. Hawk-Eye was originally a British company but is now part of Sony. The other is GoalRef, which is a German-Danish company.

Q: Any major differences between the two approaches?

A: Yes, and they are significant. Hawk-Eye uses cameras to determine the ball's position. GoalRef does so through use of a chip in the ball. What unites them is that neither has a "human element". This will not be like a referral in cricket where a third umpire watches a replay on a screen in the pavilion. Goal-line technology decisions will be made entirely by a computer.

Q: Who oversees the competition process?

A: That is Ifab (the International Football Association Board), which is in charge of any changes to the game's rules. Historically, because the rules of the game were devised in Britain, the Home Nations all have one vote each and Fifa has a bloc of four. But the key has been to carry Fifa towards rule changes rather than forcing it to adopt new technology.

Q: What is the next step in this process?

A: Contracts are being signed to hire stadiums to carry out the tests over this month and the next, with the Basingstoke-based Hawk-Eye likely to do theirs at Southampton's St Mary's ground. Then on 2 July a decision will be made at an Ifab meeting in Ukraine on the approved system. There will have to be an industry kitemark developed and a licensing procedure established. Alex Horne, general secretary of the FA, said yesterday that it will take three months to install the goalline technology around the grounds at which it would be used.

Q: Is there anything that could go wrong?

A: There is plenty. Say, for instance, the Premier League chooses to adopt the new system for next season – which is the expectation. The new system would have to be installed in the Premier League stadiums and rigorously tested. What if five more leagues around Europe want the system? The manufacturers will have to assure Ifab and Fifa that they can meet the demand for the equipment, however high.

Q: Will it be expensive to introduce the chosen system?

A: No one will want the approved system operators to cut any corners on the basis of expense. It will be a moot point as to who pays for it. As usual, the clubs will want the FA to meet the cost and the FA will want the clubs to foot the bill. But getting it tested and installed for the new season is only the beginning.

Q: It's all about that first big decision, right?

A: Exactly. It could take weeks, even months before the new technology faces a test such as the ghost goal scored by Juan Mata against Tottenham at Wembley on Sunday. Goal-line technology is a fundamental change to the game. For the first time it takes a certain type of decision out of the hands of the referee and his assistants. Up until now they have controlled everything, from the application of the laws right down to the time-keeping of the game.

Q: We would be right in thinking that the pressure is on?

A: Yes, the rigorous testing period has been enforced because football – Ifab, Fifa, the FA, all those major football nations who have backed this project – cannot allow this to fail. It is all well and good for the commentators and fans to bang on about how crucial goal-line technology is to the game but they will be the first to put the boot in to the FA if it fails in a game.

Q: And, lastly, surely the biggest question – can it work?

A: In theory it is ideal. A message to the referee within a second of a contentious goal-line incident means that the flow of the game does not need to be interrupted. It will be crucial to establish the credibility of the system early on. Television replays will be able to tell us if the correct decision was made. As long as it works consistently in those early days then trust will be built and a huge area of uncertainty in the game removed – at least at the clubs who can afford the technology.