JUDGMENT R.S. Pathak, J. - This and the connected special appeals question the order of a learned Single Judge allowing five petitions under Article 226 of the Constitution. 2. The respondent was assessed to agricultural income-tax for the Fasli years 1357 to 1362 under the U. P. Agricultural Income Tax Act, 1948. Notice of demand was issued consequent upon each assessment requiring the respondent to pay a specified sum as agricultural income-tax. The respondent paid the tax due for the year 1358 Fasli but paid only a portion of the tax due for the remaining years. Admittedly the tax liability remained in arrears for the years 1357, 1359, 1360, 1361 and 1362F. Against the assessment orders for these years the respondent appealed to the Commissioner, and obtained an order staying the realisation of the tax remaining due. The appeals were dismissed on February 27, 1958. Thereafter, on March 21, 1958 the respondent applied in revision to the Board against the appellate orders, and the Board made an interim order directing that the arrears of tax for each of the six years should not be realised provided the respondent paid a certain part of the arrears. 3. Some time after the dismissal of the appeals, when the respondent had still not paid up the arrears of tax due for all the aforesaid years, the assessing authority made an order under Section 31 of the Act imposing a penalty in varying amounts for the different years on account of the failure of the respondent to pay up the tax due. Against the orders imposing penalty, the respondent filed revision applications before the Board and contended that he was not in default because the appellate orders were communicated to him on March 14, 1958, and he had deposited the arrears of tax on April 7, 1958, within the period of one month allowed by Section 30(2). The revision applications were dismissed by the Board on February 24, 1958 on the finding that the appellate orders were communicated to the respondent on Feb. 27, 1958, and the arrears should have been paid up by March 27, 1958. 4. Aggrieved by the order of the Board, the respondent filed petition under Article 226 of the Constitution in this Court. 27, 1958, and the arrears should have been paid up by March 27, 1958. 4. Aggrieved by the order of the Board, the respondent filed petition under Article 226 of the Constitution in this Court. These petitions were allowed by Brijlal Gupta, J. on the ground that there was no justification for imposing the penalty until the questions raised by the respondent in his appeals and revision applications against the assessment orders had been disposed of, that the respondent was entitled to notice by the assessing authority of its intention to impose penalty and because of want of such notice the principles of natural justice had been contravened, and that inasmuch as upon another set of petitions for certiorari he had quashed the assessment orders which gave rise to the tax liability in question, the orders imposing penalty must also fall. 5. Three contentions have been raised on behalf of the appellants before us. It is urged that the question whether the imposition of penalties was justified upon the facts of the case was not one which could warrant the exercise of jurisdiction under Article 226 of the Constitution. There is force in this contention. It is well settled that certiorari will issue only where there is an error of jurisdiction or a manifest error of law or a breach of the principles of natural justice. Whether or not an assessee should be penalised, when he is in default and the facts and circumstances clothe the authority with jurisdiction to impose a penalty, is a matter falling within the discretion of that authority. That the assessing authority should have awaited the decision of the respondent's appeals and revision applications and the outcome of the respondent's stay applications before the Board is a matter falling within the discretion of the authority and not a consideration warranting the grant of certiorari. 6. The second contention is that the respondent was not entitled to notice before penalty was imposed and to an opportunity to be heard in the matter. This contention, we think, is not well founded. The order admittedly is a punitive measure, intended to penalise the respondent for omitting to pay the entire tax arrears within the time specified under the statute. There may be number of reasons which could justify the omission to make such payment. This contention, we think, is not well founded. The order admittedly is a punitive measure, intended to penalise the respondent for omitting to pay the entire tax arrears within the time specified under the statute. There may be number of reasons which could justify the omission to make such payment. The assessment order and the consequent notice of demand may be a nullity, having been issued by an authority which had no jurisdiction whatever in the matter. In that event, the notice of demand being nonest, there would be no liability to pay tax in the eye of law, and an assessee would be entitled to show in the penalty proceedings that consequently there was no question of any default on his part. It may also be that even though the assessee is in default there may be extenuating circumstances for his omission or failure to pay the tax due. Upon notice and an opportunity to him in that behalf, he would be able to place before the relevant authority facts and circumstances making out a reasonable case for imposing merely a nominal penalty. So long as the statute does not specify a fixed sum as penalty, the relevant authority has wide discretion in the determination of the quantum of the penalty. Consequently, we are of opinion that the orders imposing penalty upon the respondent without prior notice to him and without an opportunity to be heard are bad in law. The contention of the appellants to the contrary must be rejected. 7. The last contention of the appellants is that the learned Single Judge has erred in holding that because the assessment orders have been set aside, the penalty orders must also fall. It seems that in the instant case the assessment orders were quashed because they were found contrary to law. They were not found to be wholly without jurisdiction and consequently a nullity. An order which is not a nullity has legal effect until it is set aside. It cannot be ignored. The assessment order and the notice of demand following it had full legal effect, and the respondent was bound to deposit the tax required of him. The liability to make that payment flowed from the notice of demand. The liability continued so long as the notice of demand was not quashed. It cannot be ignored. The assessment order and the notice of demand following it had full legal effect, and the respondent was bound to deposit the tax required of him. The liability to make that payment flowed from the notice of demand. The liability continued so long as the notice of demand was not quashed. In failing to make the payment within the time allowed to him, the respondent was clearly in default. Consequently, he was liable to penalty. We are, therefore, unable to agree with the learned Single Judge that because the assessment orders were quashed the penalty orders must fall. 8. As we have held that the respondent was entitled to notice and to an opportunity of be heard before the penalty order were passed, we are of the view at the order of the learned Single Judge must be upheld. 9. The instant appeal fails and is dismissed with costs. Since we quash the impugned order only on the ground that no opportunity had been given to the respondent to show cause against it, it will be open to the assess authority to pass a fresh order under Section 31 after giving an opportunity to the respondent show cause against it.