The British authorities maintain a comprehensive set of figures on abortion, which includes a classification by country of residence.
In a typical year, women who give their address as the Republic of Ireland account for two-thirds of non-resident women having an abortion.
The figures show that the 1983 “pro-life” amendment had no visible impact on the rising trend of Irish women travelling to Britain for an abortion.
Their numbers had begun increasing significantly in the 1970s and this trend continued through almost three succeeding decades.
The figure for Irish abortions in England and Wales peaked in 2001 at 6,625 before beginning a slow but steady decline right up to 2011, when 4,149 abortions were carried out on Irish-resident women.
The Irish Times has compiled the figures from data provided by the British department of health and office of statistics, and from archived articles of this newspaper.
Figures could not be obtained for four years in the 1980s and 1990s, but an average was used to calculate the overall estimate.
The British figures are subject to a number of caveats. They do not include Irish women who travelled for an abortion but gave a UK address. They could include women of other nationalities who gave an Irish address. They do not include abortions carried out on Irish women in Scotland, which does not compile statistics for non-residents.
In addition, more Irish women have begun travelling to other European countries for an abortion, though their number is likely to be small compared to the UK figures.
Of the abortions carried out on Irish-resident women last year, 37 involved girls aged under 16, and 111 related to 16-17-year-olds. Some 1,404 related to women in their 20s and 1,801 to women in their 30s. Some 257 were performed on women in their 40s.
Studies show that Irish women who travel to the UK tend to have abortions later in their pregnancies than British women availing of local services.
In 1970, just 261 Irish women were reported to have travelled to Britain for an abortion, but the following year this more than doubled to 577.
By 1973, the number had reached 1,200 and, by the end of the decade, 3,000.