From the Third Umpire's Screen to the Blockchain Ledger: The Chain of Custody of a Review Decision

From the Third Umpire's Screen to the Blockchain Ledger: The Chain of Custody of a Review Decision

On 14 July 2026, at Lord's, the last over of a World Cup final. Trent Boult's throw flew at a running Ben Stokes, struck the bat and ran to the boundary rope. The on-field umpires signalled throw, overthrow, six runs. The match went to a Super Over, the Super Over tied, and under the boundary-countback clause written into the ICC playing conditions, England were champions. That night I opened the Laws again — Law 19.8, the clause that says what happens when a fielder's throw strikes the bat of a batter who is running. The MCC's subsequent clarification made it plain: the batters had not crossed for the second run when the throw was released, so five runs should have been added, not six. The result did not change, but how a decision is born out of a misreading of a clause became visible in one stroke.

Nobody at the press conference asked: who read the clause? Which reader, at which layer, saw which piece of information first? Every cricketing dispute — the fury over Umpire's Call on DRS, boundary countback, frame-by-frame stumpings, even the recent calls to preserve decisions on a blockchain — ends up standing on that single question.

Context: the birth of the review and a hierarchy of readers

On 23 July 2026, at the Sinhalese Sports Club in Colombo, the Decision Review System was used in a Test match for the first time, in Sri Lanka versus India. I was thirteen, in Sri Lanka, in front of a television. The ball's path was rotated across the screen a few times, then the verdict came. It took no time at all to understand that the real event was not happening on the field; it was happening in a room, in front of a few monitors, where the person seated held more power than the cricketer.

The architecture has changed layer by layer since. At the 2026 World Cup the technology was not present in every match; cost and broadcaster set-up meant it was used only in part. In Tests each team receives two reviews, in ODIs and T20Is one. Initially a failed review was burned; later the ICC changed the rule — if the outcome is Umpire's Call, meaning the on-field decision stands, the team keeps its review. A team must decide within fifteen seconds, and the time available for reading the rule before the decision is limited too.

I opened the 110-page protocol again — that time the case was a penalty, on a football pitch, in the 2026 Carabao Cup trial, when a sixty-seven-second review at Arsenal versus Doncaster ended with no penalty. The Carabao Cup trial did not invent VAR. It revealed who could read the rule. Cricket's rulebook is thicker, and the decision room is more crowded than football's.

Core analysis: five layers, five readers

A review is never the work of one machine. Ball-tracking cameras supply data, an operator processes it, the third umpire decides, the broadcast director chooses which frame the viewer sees and when, and the scorecard makes it permanent. There is a human at every one of those five layers, and each holds a different kind of power.

The least-discussed fact about ball-tracking is that the path beyond the point of contact with pad or stump is no longer recorded — it is predicted. What the camera saw is a model; frame rate, camera calibration, pitch pace, seam orientation are all inputs. What the spectator watches feels like seamless proof; it is a forecast whose uncertainty hides in a decimal place. Technology that predicts can never make the language of hitting or missing exact — it can only define a boundary.

The second layer is messier. A review's data stream is usually generated from the host broadcaster's camera set, which is to say the host board and broadcast interests are directly involved. How many frames per second, from which angle, which camera is live when — that is a production decision, not a law decision. The ICC has mandated independent set-ups at some tournaments, but at league level the picture is uneven. Same technology, different standard — and that variance in standard can turn a series.

A chain of custody forms around every decision, and nobody publishes it: sensor to operator, operator to third umpire, umpire to screen, screen to scorecard. How long any frame is retained, which model version was running, whether anything looked wrong in calibration — the ordinary spectator never receives answers. The list of those archived questions in my notebook has grown longer every year. Error rarely happens in the camera; it happens in the hierarchy of reading — who sees which information first, and who holds the final right of interpretation.

Frame rate itself is a political number. If a camera captures more frames per second, whether the ball grazed the edge is caught with greater precision; production cost rises too. So 'no evidence' often means 'no evidence at that resolution'.

This is where the blockchain question enters. Let me be plain: I have no evidence that decision data in cricket already sits on-chain, and no publicly announced league is yet putting a decision log on a chain. What exists is at the fan-product layer — in 2026 the ICC announced a partnership with FanCraze for digital collectibles, and Cricket Australia has brought digital collectibles to market. Boards are comfortable with the technology, but the door is shut at the decision layer.

An append-only ledger is easy to imagine: match ID, over and ball, operator ID, model version, a cryptographic hash of the frame set, the third umpire's decision and a timestamp — signed and public within two minutes. With zero-knowledge proofs, a third party could verify that the third umpire and the operator saw the same frames without exposing the proprietary internals of the model. For audit purposes that is real progress, because the question stops being 'has anyone altered the record' and becomes 'what information was the decision based on'.

But a blockchain cannot detect a wrong decision. The boundary of Umpire's Call — whether half the ball is in contact with the stump — is a modelling and rule-making choice authored by the ICC and the technology supplier, not by hardware. On-chain, it will not change; it will merely become permanent. When a wrong decision is immutably recorded, we immortalise the error rather than reduce it.

The numbers display that hierarchy. On 16 June 2026, in the France versus Australia group match, an eighty-second review produced the first VAR-awarded penalty in World Cup history; Antoine Griezmann scored and France won 2-1. In the 2026 Carabao Cup trial, a sixty-seven-second review ended with no penalty and Arsenal won 1-0. Football's threshold is 'clear and obvious error'; cricket's is 'conclusive evidence' plus Umpire's Call. Different processes, same pressure — the decision always lands on the shoulders of the person sitting in front of the screen.

Contrarian view: the crowd wants certainty, the system cannot read

From the noise of the stands a belief emerges: the machine will get it right, the human will get it wrong. From that Colombo night in 2026 to now, screens have grown, cameras have multiplied, review times have fallen. Has controversy fallen? No — it has simply moved from the field into the review room. In cricket a side gets only one or two reviews per innings; every review carries a strategic calculation, and behind every Umpire's Call sits an invisible ledger of loss. The crowd reads it as luck; the system is counting.

Honesty is needed here, because the easy critique is itself a trap. The weakness of the blockchain demand is not that the technology is worthless; it is that it intervenes at the wrong node. Where the problem is tampering, an immutable record genuinely raises the cost of manipulation, and in markets with fragile stability the fear of fixing is not imaginary. But where tampering is unproven, demanding a public ledger straight away is a cheap solution: an impossible promise to a board, theatre for the audience, and the real problem — who is reading the law, who is running the model, who is disclosing nothing — stays exactly where it was. The history of law-making suggests power changes more slowly than technology.

Takeaway: three questions for the 2026 cycle

Three questions in the coming tournament cycle would leave no room for excuses — whether technology suppliers publish a calibration register, whether any league puts decision hashes on a public chain, and whether the next rule revision talks about technology or about the hierarchy of readers. If the answer to the third is hierarchy, DRS genuinely changes — not from the screen, but from the right of interpretation. The question is not technological but institutional: do we want final decisions, or correct ones?