A little data on tax rates and tax collected in the UK from
http://www.guardian.c.../25/tax-receipts-1963
1971-72 24.6 41.5
1972-73 26.3 39
1973-74 29.7 39.5
1974-75 37.9 42.1
1975-76 47.9 42.7
1976-77 56.4 43
1977-78 62.9 41.3
1978-79 69.8 40.1
1979-80 85 40.5
1980-81 100.9 42.2
1981-82 119.5 45.4
1982-83 129.7 45.1
1983-84 137.9 44.1
1984-85 147.6 43.9
1985-86 157.8 42.7
1986-87 164.6 41.6
1987-88 178.9 40.6
1988-89 197.1 40.2
The first column is revenue collected in pounds, the second is revenue collected as a % of GDP. Both in absolute and relative terms, tax revenues collected rose as top and base tax rates were reduced throughout the 1980s. High tax rates do kill the incentive to work harder (there is substantial academic research supporting this point as well).