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What is a cookie?

A cookie is a small piece of data or message that is sent from an organisation's web server to your web browser and is then stored on your hard drive. Cookies can't read data off your hard drive or cookie files created by other sites, and do not damage your system.

However, you can reset your browser so as to refuse any cookie or to alert you to when a cookie is being sent. Web browsers allow you to control cookies stored on your hard drive through the web browser settings. To find out more about cookies, including what cookies have been set and how to manage and delete them, visit

At Grant Thornton UK LLP (and its wholly owned subsidiaries in the UK) we only use cookies to monitor the performance of our website and to improve user experience.
If you choose not to accept our cookies, some of the features of our site may not work as well as we intend.

Cookies used by Grant Thornton UK LLP's websites

Cookie type Cookie name Purpose
Google analytics _utma
These cookies are used to monitor the performance of our site. We use the information to help us improve the site. The cookies collect information in an anonymous form, including the number of visits to our site, where visitors have come from to the site and the pages they visited. To opt out of being tracked by Google Analytics across all websites visit
AdInsight adiV -
adiLP -
adiVi -
We use 'AdInsite' on certain pages to track visits and repeat visits to specific pages on the site. The cookies contain no personally identifiable information.
The 'adiV' cookie contains an identifier number which is used by 'AdInsight' to track a visitor over time. This allows 'AdInsight' to show multiple visits made by a customer over time from the same browser. This cookie is set to expire 1 year after the visitor leaves the website.
The 'adiLP' cookie is used to help track visitor's who have multiple tabs open in the same browser to prevent errors in tracking.
The 'adiVi' cookie contains an identifier number which is used by 'AdInsight' to help track a visitors path while they are on the website. This cookie is set to expire 30 minutes after the visitor leaves the website.
Content Management System (EPiServer) .EPiServerLogin
These cookies are used by our content management system and not relevant to site visitors, only Grant Thornton UK LLP employees who edit and administer the site.
Content Platform cookies ARRAffinity
Used to distribute traffic to the website on several servers in order to optimise response times.
This is used to track the number of visits to the website.
.Net cookies ASP.NET_SessionId This cookie contains the user's session ID and the cookie will expire at the end of the session (when you close your browser). The ASP.NET_SessionId cookie sent to the web browser is used when you open the browser and then go to a website that implements ASP.NET session state. This cookie is deleted when you close your browser.
Glassbox _cls_s
We use Glassbox, an analytics tool, in order to identify usability issues in regards to customer journeys. Glassbox records customer sessions, and may record mouse clicks and movements, page scrolling, form input and mobile gestures. When you visit our website, Glassbox may log your IP address to collect geographic information on our site visitors.
Data gathered by Glassbox is for Grant Thornton’s internal use only. For more information and to find out how they use cookies, view Glassbox's privacy policy.
Siteimprove  nmstat This cookie is used to help record the visitor’s use of the website.
It is used to collect statistics about site usage such as when the visitor last visited the site.
This information is then used to improve the user experience on the website
Youtube preferences PREF
We use YouTube to embed a selection of videos in our Thinking and campaign pages. The embedded videos do not set cookies themselves and can be played with no cookies set. However, if the 'Share' button is clicked YouTube will set cookies. The VISITOR_INFO1_LIVE cookie attempts to estimate your bandwidth and the use_hitbox and PREF cookies increment the 'views' counter on the YouTube video and stores session preferences. These cookies don't gather information that identifies a user.
Marketo Munchkin _mkto_trk These cookies are set by Marketo, our marketing automation platform and enable us to monitor and improve our communications and services.
This allows us to track visitor behaviour on our website, and to link a visitor to the recipient of an email marketing campaign, to measure campaign effectiveness. Tracking is performed anonymously until a user submits a form and becomes identifiable.
Authentication userID
These cookies apply to registered users of our IR35* R&D**and Inclusion Insights*** platforms, and contain the user's session ID and session data, allowing the platforms to recognise logged-in users and communicate with the backend server. Each cookie will expire at the end of the session (when you close your browser). These services are managed by Edisonda Ltd, acquired by Grant Thornton Poland and a development agency Nonstop.
*Contractor monitoring management software
**R&D claims process management software
***Inclusion and diversity assessment software