Gigahertz Peaked Spectrum sources from the Jodrell Bank VLA Astrometric Survey - I. Sources in the region 35 degrees <=delta <= 75 degrees

Observations with MERLIN1 at 408 MHz have been used to establish the low-fr equency part of the spectra of more than a hundred compact radio sources ta ken from the part of the Jodrell Bank-VLA Astrometric Survey limited by 35 degrees less than or equal to delta less than or equal to 75 degrees. These sources were selected from JVAS and other catalogues to have convex spectr a between 1.4 and 8.4 GHz, characteristic of Gigahertz Peaked Spectrum (GPS ) sources. We have confirmed convex shapes of the spectra of 76 objects (on e half of our initial candidates) thereby yielding the largest genuine samp le of GPS sources compiled so far. Seven of 17 identified quasars in the sa mple have large (z greater than or similar to 2) redshifts.