I have a list like this

```
data = [('£3.46', 'I001'), ('£10.46', 'I002')] 

```

I want to sort this list with

```
data.sort()

```

however the sorted list puts £10.46 before £3.46, I'm assuming this is because the data is a string and £1 comes before £3.  

I have tried looking at lambda functions but I can't get my head around it.