I am trying to format a date such that it always shows as UTC e.g. in the format 'dd/mm/YYYY HH:MM UTC'. So far I have this code:

const options = {
    year: 'numeric',
    month: 'numeric',
    day: 'numeric',
    hour: 'numeric',
    minute: 'numeric',
    timezone: 'UTC',
    timeZoneName: 'short'
};

const formattedTime = new Intl.DateTimeFormat('en-GB', options).format(new Date(unixTimestamp))

However this gives me a time in either GMT or BST, e.g.

24/11/2021, 05:51 GMT
27/10/2021, 05:09 BST

What I would like is for the time to be always shown as UTC so in the case of the above examples:

24/11/2021, 05:51 UTC
27/10/2021, 04:09 UTC

Is there a way to configure DateTimeFormat to do this or should I be using something else? I'd rather not resort to importing a library if at all possible.