The pound remained slightly below Monday's highs during early Asian trade despite positive GfK data, amid mixed market response to the likelihood of a Greek default.
Traders also waited for the first quarter GDP data revision by the UK due later in the day.
At 5.30 GMT, the GBP/USD traded 1.5723, little changed from the previous close of 1.5726. The pair had traded as high as 1.5788 on Monday.
Sterling had traded as high as 1.5929, a near seven-month-high, on 18 June, from where it is now off 1.7%. The UK currency still has room on the downside, to keep the uptrend since mid-April alive.
Charts show that only a break below 1.5400 will weaken the upward trend. As long as that level holds, the GBP/USD pair has risks more skewed to the north. The levels to watch then will be 1.5929 first and then 1.6000 ahead of 1.6180.
On the downside, 1.5535 will be of some importance ahead of 1.5400, and beyond that 1.5160 and 1.4960 will be the levels worth watching ahead of the April lows.
Greece's Prime Minister Alexis Tsipras hinted on Monday (29 June) that he might resign if the Greek people vote in favour of the creditors' bailout terms.