One of the basic definitions of an uptrend is a series of higher highs and higher lows. Using the same theory, a downtrend is characterised by a series of lower highs and lower lows. Using the outer price channels can help you identify this. I like to look for what I call the staircase effect. However, changing the timeframe you look at may give a different picture.
For example, the daily FTSE chart shown below clearly shows that the June lows created a lower low, and it is possible that it is currently in the process of forming a lower high.
However, if you look at the weekly FTSE chart (shown right at the bottom), then this shows a different picture - the June lows coincided with the early 2012 highs - a case of resistance now acting as support? That chart shows that a series of higher highs and higher lows, and therefore the current uptrend, is still intact. The stairs are moving up.