Cookies
Find out more about how cookies are used on GOV.UK and how to manage them.
How we use cookies
Sessions
We set a cookie to record your session activity.
| Name | Purpose | Expires |
|---|---|---|
| mdtp | Stores session data | When you close your browser |
| mdtpp | Stores session data | When you close your browser |
| mdtpdf | Stores session data | When you close your browser |
| mdtprc | Stores session data | When you close your browser |
| mdtpolpb | Gives user access to GOV.UK One Login Beta | 180 days |
| mdtpdi | This is used to uniquely identify a device that has interacted with tax services, for internal security auditing | 10 years |
| DEVICE_SESS_ID | Remembers a successful sign in using an access code | 7 days |
| PLAY2AUTH_SESS_ID | Stores session data | 24 hours |
| PLAY_FLASH | Stores session data | When you close your browser |
Our introductory message
You might see a pop-up welcome message when you first visit. We store a cookie on your computer so it knows you've seen it and not to show it again.
| Name | Purpose | Expires |
|---|---|---|
| seen_cookie_message | Saves a message to let us know you've seen our cookie message | 1 month |
Our user research banner
You might see a banner about user research when you visit. We store a cookie so your computer knows when you do not want to see it again.
| Name | Purpose | Expires |
|---|---|---|
| mdtpurr | Saves a message that you do not want to see it again. | 1 month |
Measure website usage (Google Analytics)
Google Analytics software collects information about how you use the site. We do this to make site improvements and make sure it’s meeting your needs.
Google Analytics stores information about:
- the pages you visit - how long you spend on each page
- how you got to the site
- what you click on while you're visiting the site
We do not pass any personally identifiable information to Google Analytics (eg your name or address) so they can’t use this information to identify who you are.
| Name | Purpose | Expires |
|---|---|---|
| _gat | This helps us identify how you use GOV.UK so we can make the site better | 10 minutes |
| GDS_successEvents and GDS_analyticsTokens | These help us identify how you use GOV.UK so we can make the site better | 4 months |
| _ga | This helps us identify how you use GOV.UK so we can make the site better | 2 years |
| ga_nextpage_params | This stores data to be sent to Google on the next page you request | When you close your browser |
You can opt out of Google Analytics cookies (opens in a new tab) .
Comparing different versions of webpages (Optimizely)
Sometimes we use Optimizely software to test different versions of webpages to see which performs better. We do this to make site improvements and make sure it’s meeting your needs.
| Name | Purpose | Expires |
|---|---|---|
| optimizelyEndUserId | This helps us identify how you use GOV.UK so we can make the site better | 6 months |
| optimizelyRedirectData | This helps us identify how you use GOV.UK so we can make the site better | 5 seconds |
You can opt out from having Optimizely collect your information by visiting their opt out page (opens in a new tab) and entering our Developer Hub URL in their opt out form:https://developer.service.hmrc.gov.uk/api-documentation
Our satisfaction survey (Optimal Workshop)
We use Optimal Workshop (opens in a new tab) to collect responses to our survey. If you take part, Optimal Workshop saves cookies to your computer to track your progress.
You can find out more about the cookies that Optimal Workshop uses (opens in a new tab).