I have issued a signed blank cheque to my friend as a surety for 10,000/- that I have taken from him 2 years back. At the same time I also gave him a signed ( on the revenue stamp for Rs.1/-) blank promissory note to him. This I have done in good faith. Now when I tried to give him the money back with interest, he says that he gave me Rs.50,000/- and to that extent he is threatening me to go to court. After going through the cheque that he had shown me I understood that he had filled the cheque with his name, figure Rs.50,000/- and in words by closely imitating my writing with the same ball point ink (blue). I am afraid whether I have to pay Rs.50,000/- if he files a case in the court. Please tell me whether I can prove that the time of my signature and the time of filling up the spaces of cheque are different. What are the latest court rulings? Please tell me what is the way out?