After spending a major part of the European session below 1.4700 handle, the GBP/USD pair finally broke on the upside and is now trading at session high level.As the NA trading session got underway, a fresh bout of US Dollar selling pressure seems to have assisted the pair to surpass and build on to its gains above 1.4700 handle. On Tuesday and ahead of the US opening on Wednesday, traders seemed reluctant to carry their long bets going into Thursday's crucial Brexit referendum. Despite of the recent poll results that although showed lead to the 'Remain' camp, uncertainty persists as the support is still evenly distributed between the two camps. Later on Wednesday, a couple of polls will be released and the pair runs the risk of a sudden turnaround in the sentiment, should the poll result show 'Leave' camp regaining the lead.Nevertheless, the pair is likely to remain volatile heading into Thursday's critical referendum vote in the UK that would decide country's future in the European Union.Technical outlookValeria Bednarik, Chief Analyst at FXStreet notes, "The pair´s 4 hours chart shows that the technical indicators have turned strongly lower, still correcting the overbought readings reached earlier this week, but given that the price remains well above a bullish 20 SMA and in consolidative mode, the downside potential is limited.""A downward corrective movement can extend down to 1.4590, but buying interest is expected to surge around it, containing the downside. The daily high has been set at 1.4715, and gains beyond it should see the pair extending towards the 1.474/70 region, but fresh highs are not expected for today."