The Celtic Sea was affected by thick, dynamic and very extensive glacier ice during the Late Devensian. But the ice was NOT contained within an ice stream.......
About ice streams (Bethan Davies):
Ice streams are corridors of fast flow within an ice sheet (ca. 800 metres per year). They discharge most of the ice and sediment from these ice sheets, flowing orders of magnitude faster than their surrounding ice. Their behaviour and stability is therefore essentially important to overall ice sheet dynamics and mass balance. The Antarctic Ice Sheet currently discharges 90% of ice and sediment through ice streams. Antarctic Ice Streams are fed by complex tributaries that extend up to 1000 km into the interior of the ice sheet.
Ice streams can be constrained by topography or by areas of slow moving ice. They are called topographic ice streams or pure ice streams respectively. Both types show variations in behaviour (both through time and space), which indicates potential for instability and are therefore particularly interesting.