Figures seen by the Guardian show lengthy wait times for diagnostic tests such as ultrasound and CT scans

Some patients in England are waiting up to two-and-a-half years for important diagnostic tests such as ultrasound, MRI and CT scans, according to figures seen by the Guardian.

The longest waits were two-and-a-half years for an MRI scan, almost two years for an ultrasound and a year for a CT scan, responses to freedom of information requests by the Liberal Democrats show.

People with heart problems are among the worst affected. Examples from NHS trusts included a 49-week wait for an echocardiogram and a 475-day wait for an angiography.

Under the NHS constitution, patients should wait less than six weeks for diagnostic tests. The target is for only 1% to wait more than six weeks, but now 25% of all patients do so, according to research from the House of Commons library, commissioned by the Lib Dems.