Can I drive in Northern Ireland with only a small part of the windscreen cleared?

No. Clearing only a small “letterbox” area of the windscreen is not consistent with the Highway Code requirement to be able to see properly.

Restricted vision can hide pedestrians, cyclists, junction traffic and hazards at the edges of the road.

For “Can I drive in Northern Ireland with only a small part of the windscreen cleared?”, the wider Northern Ireland context is this: Northern Ireland winter driving is especially sensitive to changing road-surface temperature, rain, ice, flooding and exposed routes. Official advice is to drive for the conditions actually in front of you, not for the posted speed limit or the fact that a road was treated earlier. TrafficWatchNI and current weather warnings are the right live sources when conditions are deteriorating.

For this exact question — “Can I drive in Northern Ireland with only a small part of the windscreen cleared?” — the practical point is: Clear and demist the full area needed for safe visibility before the car moves. The answer should be applied to the actual signs, conditions, licence wording or parking rules in force at the time, because temporary restrictions and individual DVA decisions can change the ordinary position.

This Northern Ireland-specific page on “Can I drive in Northern Ireland with only a small part of the windscreen cleared?” was checked against the attached official sources before publication, with nidirect/DVA and the Northern Ireland Highway Code used ahead of generic UK motoring articles. If the rule, road layout or personal licence condition changes, those primary sources are the ones to re-check.