Would this investment idea work?

Say I were to buy several thousand cigarettes, vacuum-seal them so here was no possibility for degradation, then just leave them unopened until the price of cigarettes had increased enough for them to be saleable at a decent profit, after covering the original cost of sealing the cigarettes air-tight and any storage fees (which could be avoided altogether, if I kept the amounts small enough) .....

Would that be legal? I mean, the duty on the cigarettes would already have been paid when they were originally bought. and every year all the tobacconists are offering fags at pre-budget prices for a few weeks, so it must be legally permissible to sell them without paying any extra duty on them.