Richard Kettleborough, one of the on-field umpires in the ongoing second Test between England and Pakistan, has been spoken to by the ICC's anti-corruption unit (ACU) after taking to the field wearing a smartwatch.

Kettleborough was seen wearing the watch during the first session of the match. ESPNcricinfo understands he soon realised his error, took off the watch and reported the incident to the ACU. He has not been seen wearing it after lunch on the first day.

ESPNcricinfo further understands that the ACU consider the incident a minor violation of the regulations. They spoke to Kettleborough and reminded him of his obligations under the Player and Match Officials Area Regulations (PMOA). They are unlikely to take further action.

In an effort to combat corruption in cricket over the last few years, players and officials have been obliged to hand over their phones (and any other transmitting devices) to anti-corruption officials ahead of the start of play. They are then locked away and returned to them shortly after stumps. The ICC also has the power to confiscate devices and download all material from them in order to monitor recent activity, but have chosen not to do so on this occasion.

Kettleborough is not the first to make such an error. Pakistan's players were spoken to by officials after taking the field wearing smartwatches during the Lord's Test of 2018. While it was accepted the devices were disabled - they can be used, when disabled, to track fitness among other things - the players were reminded the regulations prohibited them being worn at all. Again, it was not considered anything more than a minor violation.

Earlier this year, the ECB tightened up its anti-corruption guidelines by banning players from wearing smartwatches on the field of play in all fixtures, on account of the growth of live-streaming services in county cricket.

The incident will cause some embarrassment for Kettleborough and the ACU. Usually such devices are surrendered to the anti-corruption manager upon arrival at the ground on match days, and it is not clear why that did not happen on this occasion.