A rough translation of the Latin text (though out of context I may not grasp the sense of some of it) runs as follows:
"On behalf of Robert de Albriton: the king sends his greetings to the viscount of Shropshire.
Know that Robert de Adbrichton, clerk, has not escaped from our prison (de Neugaf?? is this a place name?) by breaking out, but rather we have ordered him to be freed in response to the petition of the venerable father the bishop of Coventry and Lichfield, in whose bishopric he (Robert) dwelt.Therefore I have instructed you lest you hassle the aforementioned Robert unjustly.
With the king as witness at Gloucester, 11 June."
The medieval Latin is a bit strange, but I hope that this is helpful.