A quick round up of the current Unmetered ISP's on offer in the UK, this is not a 'comprehensive guide', just a helper. Performance rating is based on how fast the service is and how frequently problems occur. Note that we can't always be 100% accurate on such issues.

If you can't decide which one to use then you might want to try our "Which Unmetered ISP Should I Use?" page which can be found HERE, It's only simple but should at least give you some ideas.

Active Unmetered ISP's (24/7)

These are unmetered ISPs that have been launched recently or several months ago. Performance ratings can change from day to day so these may already be invalid =).

Breathe (Modem + ISDN 64k)
6 hour cut off. £50 for life.
Bandwidth Provider: ?
Problems: Problems with speed at start - improved now.
Current ISPreview Performance Rating: 3/5
ISPreview Value Rating: 5/5

Callnet0800 (Modem Only)
£20 setup charge reimbursed in phone calls. Price is £0.00.
Bandwidth Provider: ?
Problems: Tends to be a little slow.
Current ISPreview Performance Rating: 2/5
ISPreview Value Rating: 5/5

Excite0800 (Modem + ISDN 64k)
Setup fee £100. £20 per year. BEWARE: No downloading large files, streaming media or multiplayer are allowed.
Bandwidth Provider: ?
Problems: Currently slowing down as more users join.
Current ISPreview Performance Rating: 3/5
ISPreview Value Rating: 3/5

Freeserve Time (Modem + ISDN 64k)
£10 calls per month on their Telephone Network.
Problems: Some random cut offs and dead connects.
Bandwidth Provider: Planet 
Current ISPreview Performance Rating: 4/5
ISPreview Value Rating: 4/5 

Lineone (Modem Only)
£20 setup and £5 month on phone calls through adaptor.
Bandwidth Provider: BT 
Problems: Engaged tones and slow speeds.
Current ISPreview Performance Rating: 3/5
ISPreview Value Rating: 4/5

NTL World (Modem Only)
Free to NTL Cable TV customers and BT customers it is £10 setup and £10 month in calls through adaptor.
Problems: Slow CD distribution.
Bandwidth Provider: NTL
Current ISPreview Performance Rating: 5/5
ISPreview Value Rating: 4/5

RedHotAnt (Modem + ISDN 64k, 128k)
£30 setup and £30 per year.
Problems: Unresponsive support, speed improving, be wary as could decrease again soon.
Bandwidth Provider: ?
Current ISPreview Performance Rating: 4/5
ISPreview Value Rating: 4/5

Surfsaver (Modem + ISDN 64k)
Purchase £39 of shares in them and access comes as a bonus.
Problems: Slow signup process, hard to get through on Telephone, Un-fixed DNS Timeout problems.
Bandwidth Provider: Planet
Current ISPreview Performance Rating: 4/5
ISPreview Value Rating: 4.5/5

Visual Depth (Modem + ISDN 64k)
£25 setup. £75 per year. 
Problems: Slow signup process.
Bandwidth Provider: ?
Current ISPreview Performance Rating: 4/5
ISPreview Value Rating: 3.5/5

World Online/Screaming.net (Modem Only)
£20 setup. £14.99 per month line rental. Have to switch from BT to World Online Telecom.
Problems: Slow Mail Server and late bills.
Bandwidth Provider: Level3
Current ISPreview Performance Rating: 4/5
ISPreview Value Rating: 4/5

X-Stream 0800 Trial (Modem + ISDN 64k)
Free
Problems: Impossible to Connect to.
Bandwidth Provider: Level3
Current ISPreview Performance Rating: 0.5/5
ISPreview Value Rating: 5/5

Inactive/Announced Unmetered ISP's (24/7) 

Most are BT Surftime ISP's. £19+ Unmetered.

0800Freedom
24-7Freecall
Altavista
AOL
BT Click 
Games-World.Net
Intensive.net
LibertySurf
Madasafish
PlusNet (Surftime)
PurpleNet
Virgin
Zoom Free

Unmetered ISP's (NOT 24/7)

These are ISPs that offer unmetered access, but only for small portions of time, such as 'evening only access' etc.

BT Internet (Modem + ISDN 64k)
Weekends + Evenings (6pm-12). £10 per month.
Problems: Slow connections, bad pings, routers, dialup.
Bandwidth Provider: BTnet
Current ISPreview Performance Rating: 3/5
ISPreview Value Rating: 3/5

Claranet (Modem + ISDN 64k)
Weekends + Evenings (6pm-2am). £10+ per month.
Bandwidth Provider: ?
Problems: Occasional DNS Timeouts, unstable multiplayer pings.
Current ISPreview Performance Rating: 5/5
ISPreview Value Rating: 4/5

F9 (Modem + ISDN 64k)
Weekends. £10 per month.
Bandwidth Provider: PlusNet
Problems: Slow Speeds, weekend 0800 engaged tones, inability to support some offered services.
Current ISPreview Performance Rating: 3/5
ISPreview Value Rating: 3/5

IC24 (Modem + ISDN 64k)
Weekends (9am-5pm). £0.
Bandwidth Provider: C&W
Problems: Quite Hard to Connect to.
Current ISPreview Performance Rating: 1/5
ISPreview Value Rating: 4/5

StrayDuck (Modem + ISDN 64k, 128k)
0800 one week in three 0800 is average of 0845. £0.
Bandwidth Provider: ?
Problems: Some connection problems.
Current ISPreview Performance Rating: 5/5
ISPreview Value Rating: 2/5

PurpleNet (Modem + ISDN 64k)
Various freedial hour packages (ClaraNet clone). £6.49+.
Bandwidth Provider: ?
Problems: None.
Current ISPreview Performance Rating: 5/5
ISPreview Value Rating: 3.5/5

Broadband

BTopenworld
Blueyonder