There is certainly a lot of anecdotal evidence pointing to some form of psychic link between twins, both identical and fraternal.

For example when Ross McWhirter was shot dead by IRA gunmen one November evening in 1975, his identical twin Norris collapsed at his home 30 miles away; his family thought he had suffered a heart attack.

Like this story there has been plenty of of other anecdotal evidence but attempts to probe the supposed links min a more scientific manner have met with only mixed success. In 1993, a study by parapsychologist Dr Susan Blackmore found that twins asked to draw whatever came into their minds were more likely to produce similar drawings than non-twins but she concluded that this was because twins tend to think alike, rather than share their thoughts telepathically.

Other tests have looked at whether changes in the brain activity of one twin can trigger a similar change in their sibling. In 1965, the prestigious US journal Science published the results of a CIA-backed experiment suggesting the brain wave patterns of identical twins could show signs of such linkage; the evidence was hardly compelling, however.

More impressive results emerged in 1994 from a team at the National Autonomous University, Mexico, which found evidence of linked brain activity in around 25% of people with a close emotional bond.

In short : there is some evidence suggesting that twins – especially emotionally close ones – may have some special “link” but in the absence of a large, thorough study, it’s far from compelling.