There are lots of televised masses; some need to be watched live, others are recorded and can be joined at your leisure.
(Updated on 7 May 22.)
The Bishops’ Conference for England & Wales offers numerous streaming services and encourages you to put in a postcode to see which local options are available to you. This site also offers an up to date weekly schedule of televised Masses across the UK and Ireland.
There are video services available through the Diocese of Westminster.
You can also visit our neighbours in the Diocese of Arundel and Brighton and see the stream from Arundel Cathedral along with other diocesan parishes. Bishop Richard has his own page which includes his weekly podcast.
There are regular streamed services from Worth Abbey in Sussex, including a schedule of daily services.
There is a schedule of services and events from Livestream at the Shrine in Walsingham.
For broader reflections see the Southwark Spirituality Commission.
Finally, look at the link to Vatican News on YouTube for videos of recent papal services and events. Alternatively, for up to date news and other ideas, try the Catholic Herald which has a wide range of topical information.