An explanation is necessary for this list.
Britain’s Dragonflies (Smallshire and Swash) lists 47 so-called “breeding” species. However, that 47 includes Sympetrum flaveolum (Yellow-winged Darter), with which I take issue. There was a large influx of S. flaveolum in 1995/96 when successful breeding was recorded but any permanent colony subsequently disappeared. Sightings of vagrant individuals are occasionally reported but this does not, in my view, constitute a resident species. This publication, fine though it is, also numbers Anax ephippiger (Vagrant Emperor) as resident but says “breeding attempted”. Whilst individuals are recorded every year, “Vagrant” Emperor being a very appropriate name, I wouldn’t personally call it resident unless and until successful breeding is confirmed. I keep my fingers crossed.
Thus I have ended up with my UK list of 45 species.
Species which are linked to a species page, I have seen (though not necessarily in the UK). Unlinked entries, I am yet to see. As a result of a successful though weather-plagued trip to Scotland in 2017, I am now down to one species remaining to be seen.
- Calopteryx splendens (Banded Demoiselle)
- Calopteryx virgo (Beautiful Demoiselle)
- Chalcolestes viridis (Willow Emerald Damselfly)
- Lestes sponsa (Emerald Damselfly)
- Lestes dryas (Scarce Emerald Damselfly)
- Lestes barbarus (Southern Emerald Damselfly)
- Ischnura elegans (Blue-tailed Damselfly)
- Ischnura pumilio (Scarce Blue-tailed Damselfly)
- Enallagma cyathigerum (Common Blue Damselfly)
- Coenagrion pulchellum (Variable Damselfly)
- Coenagrion puella (Azure Damselfly)
- Coenagrion mercuriale (Southern Damselfly)
- Coenagrion scitulum (Dainty Damselfly)
- Coenagrion hastulatum (Northern Damselfly) 
- Coenagrion lunulatum (Irish Damselfly) 
- Erythromma najas (Red-eyed Damselfly)
- Erythromma viridulum (Small Red-eyed Damselfly)
- Pyrrhosoma nymphula (Large Red Damselfly)
- Ceriagrion tenellum (Small Red Damselfly)
- Platycnemis pennipes (White-legged Damselfly)
- Aeshna mixta (Migrant Hawker)
- Aeshna affinis (Southern Migrant Hawker)
- Aeshna isoceles (Norfolk Hawker)
- Aeshna grandis (Brown Hawker)
- Aeshna caerulea (Azure Hawker) 
- Aeshna cyanea (Southern Hawker)
- Aeshna juncea (Common Hawker)
- Anax imperator (Emperor Dragonfly)
- Anax parthenope (Lesser Emperor Dragonfly) 
- Brachytron pratense (Hairy Dragonfly)
- Gomphus vulgatissimus (Club-tailed Dragonfly)
- Cordulegaster boltonii (Golden-ringed Dragonfly)
- Cordulia aenea (Downy Emerald)
- Somatochlora metallica (Brilliant Emerald)
- Somatochlora arctica (Northern Emerald) 
- Libellula quadrimaculata (Four-spotted Chaser)
- Libellula depressa (Broad-bodied Chaser)
- Libellula fulva (Scarce Chaser)
- Orthetrum cancellatum (Black-tailed Skimmer)
- Orthetrum coerulescens (Keeled Skimmer)
- Leucorrhinia dubia (White-faced Darter)
- Sympetrum danae (Black Darter)
- Sympetrum sanguineum (Ruddy Darter)
- Sympetrum striolatum (Common Darter)
- Sympetrum fonscolombii (Red-veined Darter) 
 – Limited to Scotland.
 – Limited to Ireland.
 – Perhaps not a breeding resident but has been recorded every year since 1998.
 – May or may not be resident but if not, it seems to re-colonize and breed every year (it can manage 2 generations a season).