Guessing (based on how I obtained it) this is likely to be a Tao Geoghegan Hart (2020 Giro D'Italia winner) piece of kit, but there's no rider name listed, so can't confirm it. Regardless its a rare piece. Grab yourself a rare piece of history.
The item "Rare Genuine Team Issue Great Britain Cycling Race Fit Jersey Tokyo Olympics" is in sale since Sunday, August 22, 2021. This item is in the category "Sporting Goods\Cycling\Cycling Clothing\Tops, T-Shirts & Jerseys". The seller is "lemond868990" and is located in Winchester. This item can be shipped to United Kingdom, Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Australia, United States, Bahrain, Canada, Japan, New Zealand, Hong Kong, Norway, Indonesia, Malaysia, Singapore, South Korea, Switzerland, Taiwan, Thailand, Bangladesh, Belize, Bermuda, Bolivia, Barbados, Brunei darussalam, Cayman islands, Dominica, Egypt, Guernsey, Gibraltar, Guadeloupe, Grenada, French guiana, Iceland, Jersey, Jordan, Cambodia, Saint kitts and nevis, Saint lucia, Liechtenstein, Sri lanka, Macao, Monaco, Maldives, Montserrat, Martinique, Nicaragua, Oman, Pakistan, Paraguay, Reunion, Turks and caicos islands, Aruba, Saudi arabia, South africa, United arab emirates, Ukraine, Chile, Bahamas, Colombia, Costa rica, Guatemala, Honduras, Jamaica, Kuwait, Panama, Qatar, El salvador, Trinidad and tobago, Uruguay, Russian federation.