Candidates and lost deposits in UK General Elections since 1945

Year	45	50	51	55	59	64	66	70	74F	74O	79	83	87	92	97	01	05
Candidates	1658	1868	1376	1409	1536	1757	1707	1837	2135	2252	2575	2577	2325	2948	3724	3319	3554
Lost deposits	175^¶	461	96	99	116	186	238	408	321	442	1001	739	289	900	1569	1177	1385
Deposits as % of total candidates	10.55	24.68	6.98	7.03	7.55	10.59	13.94	22.21	15.04	19.63	38.87	28.68	12.43	30.53	42.13	35.46	38.97

^¶ excludes two-member constituencies: see discussion.

The forfeiture of deposits was introduced in 1918. Initially, candidates

in one-member and two-member seats needed to get one eighth (12.5%) of the total valid votes cast (i.e. ballot papers) to avoid losing their deposits
in seats returning three or more members candidates needed to get one eigth of the total valid votes divided by the number of seats in order to avoid losing their deposits
in STV elections, the calculation was based on the 1st preference figures in the 1st count
if they stood in more than one constituency, candidates were not able to recover more than one deposit, even if they were qualified to do so in several seats

The threshold was changed to 5% and the deposit increased to £500 in 1985.