Currently there are no 100% mortgages available to first time buyers and even if you could get a 5% deposit together you will struggle to obtain a suitable lender. This does not mean however there is not a solution to your problem.
If your parents are selling the property to you at a discount i.e. less than what is actually worth, you can use this discount as a deposit. For eg, if the property is worth £150K but they are willing to sell it to you for £100K you can potentially use the £50K as what is know as a 'gifted deposit'. The actual sale price will be detailed at land registry as £150K and assuming the mortgage lender values the property at this level they will accept the gifted deposit.
Mortgage lenders will only accept a gifted deposit if it comes from a direct family member. It is also important there is extra legal work involved in this transaction and your parents will need to take independent legal advice before considering the above.
I suggest you seek independent
mortgage advice to discuss the whole situation in much more detail and obtain a full understanding of what is available and any implications to yourself.