Petition Increase stamp duty threshold for London

This petition is to request an increase in the threshold for 3% stamp duty at the £250,000 level to £450,000 at least in London.

It almost impossible now to find a property in London which is below £250,000. Due to the 3% stamp duty being applied to any property over £250,000 this means there is a huge amount of money needed to buy a property in London on top of the deposit already required.
This is a huge restriction for many young people in London who are trying desperately to save and get onto the property ladder. Meaning that they need a minimum of £7,500 extra on top of their deposit.
I feel the current stamp duty thresholds are unrealistic. Especially when it comes to London I believe it is unfair to have the same threshold as elsewhere in the country where properties of the same size are generally significantly lower in price.